

This guide is a living document, it was last updated: 07/03/20 2020-07-03



Contents

The largest/most-complete guide to all possible classic Mac Pro upgrades covering OS, Firmware, GPU, CPU, Storage, USB and Network upgrades.

Upgrading a classic Mac Pro isn't hard. The information is out there but knowing what is possible, what questions to ask, and where to find it isn't nearly as easy. This is less a how-to guide/manual than it is a roadmap to primary sources by other brilliant people, written to be accessible to both new and advanced users. It has been continuously updated for nearly two years and will continue to be updated as long as there is a community to make new discoveries. I hope you find this guide useful.

The Cheese Grater's last stand

I've updated this intro a few times, and the inevitable finally happened, Apple announced it will be shifting to it's own ARM based CPUs. However, Apple will still sell Intel Macs for two more years suggesting several more years of support. Only time will tell. The Mac Pro community already has the Big Sur beta up and running via OpenCore and now suddenly seems unlikely that Apple will drastically alter the hardware requirements for Intel Macs moving forward. There's a slightly poetic quality that classic Mac Pro, the pinnacle of modular computing, will be there to see its end. It's too bad, Mac Pro 2019 is unlikely to share the same fate as a computer that's life span ranged into the decade mark as it seemed like a worthy albeit expensive heir. There's always the possibility that the Mac Pro may live again in the ARM future but I'm not very hopeful. ARM will be fantastic for thin laptops but it remains to be seen how Apple can compete against the big numbers AMD is generting for desktops.

If you'd like to read the old intro, click the show old intro below.

Like many, I had quite a few thoughts about the Mac Pro 2019. If you want my personal take, you can read it here.

Show old intro

Apple finally announced a new Mac Pro after the failed 2013 Mac Pro. Little did we know, the trashcan design was a multiplane metaphor, not only as an ode to planned obsolescence but to Apple's opinion of Pro users as it even failed to capitalize on providing modest updates, the computer that was meant to be replaced but without replacements. The cMac Pro (Classic Mac Pro) remains as the high water mark of Apple professional computers, easily besting even the G3/G4 era computers which made for very upgradable CPUs, GPUs, and RAM (thanks to the famed folding door design and CPU daughter cards). Regardless of what the new Mac Pro looks like, we're nearly at the end of the road for the classic Mac Pro. Apple officially dropped the 1.1 - 3.1 Mac Pro support, although (some) of the Mac Pros can be hacked to run current OSes. Thunderbolt PCIe chassis finally (sorta) officially support external GPUs making the Mac Pro a little less necessary. The iMac Pro single-core performance is double that of a Mac Pro 5.1 even with a Xeon X5690. This level of performance is bound to trickle down in the next few years to more modest Mac configurations. If the Mac Mini ever received an update to an LGA-1151 let alone an LGA 2066 and ThunderBolt 3, it'd challenge the Mac Pro 5.1. Edit: there's now an updated Mac Mini and despite the fixed CPU, its an improvement. Then there's the rumor of ARM Macintoshes in the future, in the darkest of timelines where the modular computer is killed as SOC computing takes over. Computers are locked out of OS upgrades as quickly as a phone. In this dystopian future, Apple has its way and we're on forever hardware upgrades, tossing working machines in landfills or worse Google has its way, relegating us to a hellscape of thin clients and subscription services and our own data held as bounty behind a paywall even as every bit is mined deeper like a Pennsylvanian quarry. Lastly, there's phoenix act where the Mac Pro 7.1 (2019?) is a triumphant return to a user serviceable, upgradable box replete with PCIe slots. The Mac Pro in this scenario becomes the vanguard of the current community of solder-iron wielding outcasts, cantankerous power users, and cranky creative professionals, people disaffected in the era of iOS. It'd be the unity of rejects who cling to past, not out of nostalgia but out of practicality, a mob completely ready to abandon their aging hardware. More than likely, we'll get a Mac Pro that's a middling mess, an attempt to appease Johnny Ive's ego over the requirements of its target audience. Whatever the future holds, the Mac Pro Cheesegraters are long-in-tooth, and the viability of using one as a daily driver is fading but with right upgrades has still life left. This guide is an ode to the best computer ever made, the classic Mac Pro an engineering marvel marking the high-water mark of performance, ease-of-use and user-serviceability. – Greg A quick aside for self-indulgence: I originally wrote in 2013 an upgrade guide for the Mac Pro, back in my earliest years of blogging (when this blog was hosted on Tumblr, mistaking Tumblr a utility for blogging). It was talky, anecdotal and amateurish, mostly upgrades I had done myself at various points, but also one of the first attempts at an all-encompassing guide for upgrading Mac Pros. I updated the blog post infrequently over the years, and it became a briar patch of disparate rambling, thorned with tangents and asides. I felt it reflected poorly as I've become a marginally better writer... at least that of an HS sophomore. I decided to clean up, update, and rework my blog post, but it became very apparent I should start from anew as I was already committing a wholesale field burn. The result is this guide: a roadmap to upgrades with all the relevant info and primary sources (and many words and a bit of ego-death for the sake of continuity).

A hearty thanks to all the communities and websites where Mac power users still exist: MacRumors, Netkas, XL8yourmac, TonyMacx86, EveryMac, Ars Technica and to The Mac Pro Upgrade group on FB (users Martin L, Jay V,, Gianluca M, Jean-Paul R. John C, Brennan F, Peter K, Antonio A, Adam S and many others) and Mac Pro Users on FB, (Eric Z.) for providing feedback, the guys who do a lot of heavy lifting in the community like Martin (h9826790), tsialex, Jay Fac and many users who've taken the time to email me to correct any errors. Even MacVidCards chimed in to correct this guide.

Special Announcements

Mac OS 11, Big Sur beta is up and running on classic Mac Pros using OpenCore.

Mini-Glossary of Terms / About this guide Jumping into the world of Mac OS can be daunting as there's a lot assumed tribal knowledge and history. I try to avoid unnecessary shorthand, but there are a few unavoidable terms. I like to write for as many people as possible and to remain accessible. For sanity sake, there is a base assumption for understanding but hopefully a low-enough bar that novice users can follow along and learn. We all start somewhere, and no one should ever feel bad for asking questions. Examples of assumed knowledge would be like the fundamental difference between an SSD and Hard Drive is or what CPU cores are. There are many other sources that can educate users on these topics and do a better job than I would. Even then, I try to explain core concepts or provide links when necessary to help educate a user. This means this guide is long but informative. The initial inclination will be to skip sections. However, some key information may often be discussed intros and other sections. I've tried to mitigate this, but in the GPU and storage sections, there's a lot of information to digest. If you feel that something is unclear or never adequately explained, please reach out to me and let me know as my readers are a global audience and of all walks of life and a wide variety of skillsets. I've often been humbled by people who are much more knowledgable than me. and I appreciate anyone who points out errors or novices who feel something is confusing. Please see the Changelog for more details on how to reach out to me. We all start somewhere, and I frequently question my own aptitude when I see how much heavy lifting others have done to make this guide a reality. For my more technical users, I depend on you for accuracy. This is truly a community effort. Lastly, one regrettable note for my international readers, I list prices in USD, dates Month/Day/Year, and measurements in imperial as I live on the mainland of the United States and thus also incurs some of bias that of an American English speaker. Prices differ vastly in foreign markets, and unfortunately, generally, the US is remarkably cheaper for Apple products and some hardware upgrades. Any buying advice will reflect the bias that is implicit to someone living in the US. As far as measurements, I apologize for our measurement system based on ambiguous associations with tangible objects like a child would use. APFS - Short for Apple File System, a proprietary file system used on Mac OS and iOS. File systems define how data is stored and retrieved in an operating system. File Systems, like all software, has limitations, and APFS was used to fix many of the shortcomings of HFS+. The transition to APFS was (relatively) smooth, but Apple chose not to support certain older hardware when it moved to APFS. Bits vs. Bytes - You probably know this one by heart: There are 8 bits to every byte. For this guide to avoid confusion, I use bytes instead of bits when discussing all things bandwidth related, even though networking favors bits and local storage favors bytes. It's pretty easy for mistake bits for bytes as it hinges on capitalization. 10 gigabits-per-sec is written in shorthand as 10 Gbps. 10 Gigabytes-per-second is written as 10 GBps or 10 GB/s. Converting bits to bytes means dividing by eight. 10 Gbps = 1.25 GB/s (or 1.25 GBps). Download speeds are expressed by operating systems in bytes per second, which confuses consumers as internet connections are not. For example: A 100 Mbps network connection has a maximum bandwidth of 12.5 MB/s. cMP - classic Mac Pro. Used to refer to any Mac Pro released between 2006-2012. Cheesegrater - Slang for the classic Mac Pros. I did not invent this term. This term arose to describe the billet metal on the front/back of the Mac Pros that resembles a "cheesegrater" although functionally it'd be more appropriate to use it as a pasta press. EFI - Short for Extensible Firmware Interface, a specification designed by Intel to replace BIOS as the method to interface between an operating system and the platform firmware. This former isn't essential to understand beyond that it is a computer's firmware. Apple adopted EFI on Intel Macs, and this is the interface that allows selecting a boot drive before OS X begins booting (by holding down the option), among other pre-OS loading functionality. I use the term EFI slightly loosely as I'll refer to the boot screen as the EFI even though this isn't all that EFI is providing for the Mac. Also, it is important to understand that the UEFI (Universal Extensible Firmware Interface), which is now industry standard for PCs, isn't the same as Apple's EFI on computers from 2013 and before. They are similar, but Apple's implementation varies partly due to age and partly due to the closed nature of Mac OS. Apple has since begun adopting (at least portions of it) UEFI, so the implications are better for the 2019 Mac Pro and GPUs. In order for a GPU to display a pre-boot screen, need Universal Graphics Adapter Protocol (UGA) firmware for the Mac Pro 1.1/5.1s. The more modern UEFI replaced UGA with Graphics Output Protocol (GOP), which is not used on the classic Mac Pros. 32-Bit EFI - When used in this guide, bits are pretty much limited to discussion of a CPU architecture or color depth. 64-bit CPUs can execute binaries that use 64-bit virtual memory spaces. A 32-bit CPU was limited to 4 GBs of memory space, whereas a 64-bit CPU can address roughly 18.4 exabytes. 64-bit CPUs are not faster at executing 32-bit code unless the memory thresholds are prohibiting functionality. (It's a common mistake on the internet to refer to certain Macs as "32-Bit" as almost all Intel Macs (sans the Core Duo Models) have had 64-bit CPUs. However, some of the older Macs, like the 2006-2007 Mac Pros, used 32 Bit EFI. Apple dropped support for 32-Bit EFI with Mac OS 10.12. 10.15 Catalina dropped support for 32-bit applications. DosDude1 - the handle of a prodigious Mac OS scripter who makes Mac OS installable on a large swath of older Macintoshes, under the same name, generally referred to as some variation of DosDude1 Patcher Tool for Unsupported Macs. In this guide, I refer to DosDude1 not as the person but as the scripts he has written. See his personal website. I encourage users to donate to him for his hard work. Firmware - a term you probably have heard and already possess some understanding of, the standard definition is a program that is written into Read-Only Memory (ROMs), and requires a specialized process to change (if it can be changed at all) called Flashing. Flash/Flashing - The act of writing over data that exists in an otherwise in Read-Only Memory (ROM) or space (Firmware). Hackintosh - Any non-Apple hardware that is running any version of Mac OS, generally standard PCs using a lot of workarounds. HFS+ - Short for Hierarchical File System but also referred to as "Mac OS Extended" a proprietary file system used on Mac OS, released with Mac OS 8.1 in 1998. It remained the default file system for Apple for nearly two decades, used on Mac OS 8/9, OS X, the iPod, early versions of iOS but lacked some core features found on file systems developed later. Kext - With OS X, the architecture for drivers uses kernel extensions, called .kext files. Kexts are supremely powerful and the backbone for the Hackintosh community to enable unsupported hardware. However, Apple has deprecated kexts in 10.15 Catalina for security reasons, replacing them with EndpointSecurity and SystemExtensions and DriverKit. How this affects unsupported hardware remains to be seen. Kexts are located within /System/Library/Extension and /Library/Extensions . Mac OS / OS X / macOS - Mac OS X was rebranded to Mac OS, I use these interchangeably as I have a tough time accepting macOS, as it is still OS X to me. The difference is superficial. Generally, Apple writes macOS, but I find this annoying, so you’ll see Mac OS littered through this guide. Mac OS is not to be confused with Mac OS classic (Mac OS 7.x - 9.x). Metal - Previously, Apple's default graphics library for graphics acceleration was OpenGL (Open Graphics Library), used on iOS and Mac OS. Over time, OpenGL fell behind in performance and features when compared to a library like Microsoft's DirectX. Without an ideal candidate to replace it (OpenGL's successor, Vulkan, would not be released until 2016), Apple created it's own graphics library called Metal and shipped it in 2014 on iOS 8 first.Later, Apple ported Metal to OSX. Mac OS 10.14 Mojave uses Metal to now power Mac OS. The new API does not support many old GPUs as their drivers were not updated. Regardless had Apple used Vulkan, there'd been a day of reckoning with older hardware and support. NVRAM/PRAM - Non-volatile random-access memory (previously Parameter RAM) is a space reserved for various low-level settings found on Macs pertaining to the pre-boot settings. These settings contain data such as default boot volume, back up boot volumes, default audio output, audio levels, computer's name, Keyboard language, backlight level (for laptops), whether Bluetooth is enabled, default GPU, and so forth. The contents of the NVRAM can be viewed via the terminal using nvram -xp . The difference between NVRAM vs. PRAM is transparent to the user, NVRAM uses a small storage space using flash-based storage, whereas the PRAM uses a battery to keep the settings buffered in the RAM. Occasionally, problems can arise (generally associated with hardware upgrades) that can cause problems. Resetting the NVRAM is still referred to as "zapping the PRAM". This is performed by holding down Command + option + p + r keys during boot, prior to the system chime and will cause the computer to reboot immediately and chime again. This will clear out the NVRAM. Alternatively, the NVRAM ram can reset via the terminal using nvram ​-c , which will require restarting manually for the changes to take effect. OpenCore - In the hackintosh world, utilities are usually required to facilitate booting macOS on unsupported hardware, commonly referred to as "boot loaders" like Clover. OpenCore is the latest iteration of the boot loader, designed to be more modular and stable and is useful to non-Hackintosh Macs as it can emulate EFIs allowing for additional functionality. For the Mac Pros, OpenCore can enable a pre-boot screen to pick a bootable drive, and it's UEFI emulation can be used in 10.14 to enable hardware encoding of MPEG (.h264) among other things. SIP - System integrity protection, a feature of later Mac OS introduced in OS X El Capitan, that walls off portions low-level features of Mac OS to protect it from malware. Prior, any application with root-level access could read/edit/modify system files. However, sometimes, when performing certain hacks, it requires disabling during installation and then re-enabled. There are legitimate reasons why users may want to leave it disabled. See Disable System integrity protection for instructions. See About System Integrity Protection on your Mac on Apple.com for more details. Terminal/shell - OS X is famously built on NeXTStep, which was a *nix based operating system, which gave it access to a new (old) feature, a command-line shell. This gave Mac users the ability to interact with the OS akin to Unix/Linux. Many advanced Mac OS operations can only be performed via the terminal, such as disabling SIP or enabling TRIM for an SSD. Users unfamiliar to the world of the terminal should always exercise due diligence before copy and pasting random snippets of code found on the web for the terminal. Any Mac user looking to become a power user should make an effort to learn terminal basics. The ability to operate the terminal unlocks a feature set outside of the GUI and can do many of the functions that the GUI can do. As bonus terminal skills translate to Linux and Unix, good for server management/networking or web development. Many utilities are command-line only, like the ever power ImageMagick which can batch process images much faster than GUI applications. Prior to 10.15, Apple used Bash as for its terminal but now has pivoted to ZSH. Trashcan - While Mac OS has a trash can for deleting files, in the context of this guide, this used to poke fun of the Mac Pro 2013 for its looks and lack of functionality compared to the almighty classic Mac Pro. Despite its shortcomings, I wrote The Definitive Trashcan Mac Pro (2013) Upgrade Guide.

Know your Mac Pro's Model A good portion of this guide (and others) uses terminology such as "Mac Pro 2008" or Mac Pro 4.1 or Mac Pro 6,1 when referring to what upgrades are feasible. The classic Mac Pros come in five iterations, and there are currently seven different iterations of the Mac Pro family. You can find out a Mac Pro's version by going to "About this Mac" under the Apple menu. All classic Mac Pros share a base level of specifications: Four full-length PCIe Slots, 1 mini PCIe slot for an Airport/Bluetooth card, four SATA2 3.5 drive bays, two 5.25 inch Optical drive bays (ATA on 3.1 and lower Mac Pros, SATA2 on Mac Pro 4.1+) dual Gigabit Ethernet, five USB 2.0 ports, two Firewire 400 ports, two Firewire 800 ports, and optical digital audio in/out. The differences pertain to the bus/RAM/CPUs and tray designs for RAM and CPUs. Visually from the exterior, these computers are the same and difficult to identify from each other without opening them up. Internally the 1.1/2.1s, and 4.1/5.1s are nearly identical. A 1.1 Mac Pro can be firmware flashed to a 2.1 Mac Pro, and a 4.1 can be flashed to a 5.1 Mac Pro. The best way to verify what the original computer's version was is via using its model number (or serial number). For more info, see EveryMac's Mac Pro specification section and EveryMac.com's Ultimate Mac Lookup. Mac Pro Model Name/Year CPUs Max OS Description Mac Pro 1.1 / 2006 Woodcrest 10.11.6 with Dosdude1 The first iteration of Mac Pros. The firmware can be upgraded to 2.1, uses 32 Bit EFI. PCIe 1.0. Mac Pro 2.1 / 2007 Clovertown 10.11.6 with Dosdude1 The 2.1s were released only in dual quad-core CPU configurations, 2006 dual 2x Core Mac Pros sold used the 1.1 firmware whereas the 2.1s use a slightly updated firmware. Like the 1.1 before, uses 32 Bit EFI. PCIe 1.0 + ATA for optical bays. Mac Pro 3.1 / 2008 Harpertown / Penryn 10.15.x with Dosdude1 The Mac Pro 2008s are the odd man out as there are little CPU options compared to the 1.1/2.1 Mac Pros, and the 4.1/5.1 Mac Pros, 64-bit EFI, can use modern macOS with minimal hacking. The 2008 Mac Pros lack SSE 4.2 instruction set on the CPUs as well as EPT/VT-x support, which aids greatly in virtual machine related tasks. For the most part, neither is required, although the SSE 4.2 support means using modified drivers for modern AMD GPUs. The lack of later CPU instructions means some software isn't as performant. PCIe 2.0 + ATA for optical bays. Optional SATA ports for the optical bay. The Mac Pro dual 4-core 3.1s performance is less than a single CPU 6 Core Mac Pro 5.1. Mac Pro 4.1 / 2009 Nehalem 10.15.x with Dosdude1/OpenCore The firmware can be upgraded to 5.1, uses 64-bit EFI. When flashed, they are natively supported for Mojave 10.14, depending on GPU. 4.1s tend to be the budget upgrader's choice (as historically they can be had for cheaper than a 5.1 Mac Pro). There is no performance difference between a flashed 4.1 -> 5.1 and a computer that shipped with the 5.1 firmware. However, the Mac Pro 4.1 requires delidded CPUs (see the CPU section). PCIe 2.0, no legacy ATA. Mac Pro 5.1 / 2010/2012 Westermere 10.15.x with Dosdude1/OpenCore The 5.1s are natively supported for Mojave 10.14, depending on GPU The Westermere CPUs are the highest-end CPUs supported by LGA 1366 Sockets. *Note, there were 2012 Mac Pros sold with a single Nehalem CPU, although somewhat uncommon. There is no difference between 2010 and 2012 Mac Pros beyond the CPUs and GPUs options Apple offered at the time of the sale. The Mac Pro 5.1s (or 4.1s flashed to 5.1s) have enjoyed several major firmware updates for Mojave enabling the ability to boot NVMe, which previously required workarounds/hacks to do. PCIe 2.0, no legacy ATA. Mac Pro 6.1 / 2013 Ivy-Bridge Current Also known as the "Cylinder" or "Trash can." These are radically different than the classic Mac Pro models and will not be covered in this guide. For information about this model, please visit The Definitive Trashcan Mac Pro (2013) Upgrade Guide. Mac Pro 7.1 / 2019 Xeon-W Current also known as the xMP. The Mac Pro 2019 marks a triumphant return to modularity with plenty of PCIe slots and a massive price hike. It features PCIe 3.0, the ability to have up to 28-cores, 1.5 TB of RAM. It is in a rare class of computing, doubling its predecessors' entry price.

Identifying a Mac Pro visually Mac Pro 1,1 - 3,1s sport FW400 ports whereas the Mac Pro 4,1/5,1s only have Firewire 800 ports. The easiest way to distinguish a powered off Mac Pro is by taking the side panel off. The Mac Pros, note the RAM configurations on the right-hand corner. The other sure-fire method is looking up the Serial Number. Never be fooled by a PowerMac G5 Picture provided by Peter R.M. Fitskie The Mac Pro's case is based on the PowerMac G5. The Apple tower produced from 2003-2006, which predated the Mac Pro. The G5 used an IBM PowerPC 970 CPUs and represented the last PPC Macs produced. They look exceptionally similar to the Mac Pro, but sport only one optical drive, one front-facing USB port, one firmware port, and two fans on the back, among other differences. Sometimes mislabeled listings will list the PowerMac G5s incorrectly as "Mac Pro G5s" or even as a Mac Pro. If the computer in question has one optical drive and two fans, it is a PowerMac G5, meaning it cannot run any OS later than 10.5. For more info about PowerMac G5's, see EveryMac: PowerMac G5 and Low End Mac: PowerMac G5. PCIe and you Peripheral Component Interconnect Express (PCIe or also PCI-E) is the evolution of PCI, which migrated from having a parallel bus system (where all cards in a computer competed for the same bandwidth ) to discrete connections. Regardless of how many cards are connected, it will not adversely affect the bandwidth for each PCIe card. PCIe has become the backbone of computers since its first iteration in 2003 and continues to be used, even on laptops for high-speed storage. Mac pro 1.1/2.1- PCIe layout (uses PCIe 1.0) PCI Express Slot Slot Speed 4 x4 3 x4 2 x1 1 x16 Note: The Mac Pro 1.1/2.1 allowed for lane configuration using Expansion Slot Utility

Mac pro 3.1/4.1/5.1 - PCIe layout (uses PCIe 2.0) PCI Express Slot Slot Speed 4 x4 3 x4 2 x16 1 x16

Not all PCIe slots are the same. Since its inception, there have been several updates: PCIe 1.0, 2.0, and 3.0, with the very first 4.0 PC motherboards demoed in 2018. Each iteration of PCIe radically increases the speed. Also, to add a minor bit of confusion, different chipsets have different amounts of total "lanes," the measurement of speed for a PCIe slot. PCIe slots are not all equal speed; thus, the total lanes are distributed across the PCIe slots, usually giving favor to one or two ports for maximum speed. In the case of the Mac Pros (3,1 and above), all have a maximum of 40 lanes and, thus, the lanes are pre-distributed among the PCIe slots. Since not all PCIe slots have the same amount of lanes; thus, they not all are the same speed. The amount of lanes a PCIe slot has access to is expressed numerically as follows: 1x (1 lane), 2x (2 lanes), 4x (4 lanes), 8x (8 lanes) and 16x (16 lanes). The maximum speed of each lane depends on the version of PCIe a computer has. A 1.x PCIe 1x slot has access to 250 MB/s. Thus a 4x has a maximum of 1 GB/s, and 8x has a maximum of 2 GB/s and so on. Each generation of PCIe effectively doubles the speed of a lane. A PCIe 2.0 lane is 500 MB/s and PCIe 3.0 lane is 1 GB/s. Generally, PCIe speeds are expressed in bytes, not bits. A PCIe 2.0 16x speed (8 GB/s) would be 64 Gbps (64000 Mbps). To reiterate the dramatic speed increases of PCIe based on generation: A 16x port in PCIe 1.x has a maximum of 4 GB/s, whereas a 2.x 16x port can handle 8 GB/s, 3.x is almost 16 GB/s. All PCIe slots are backward compatible; however, the caveat is that PCIe cards may not be backward compatible (this is not common). Also, not all PCIe cards will operate at the maximum port speed, as the card's chipset may limit them. Conversely, a PCIe card may support much faster speeds but will work in any PCIe slot but will be limited by the port's maximum speed. For example, you could use a GeForce 1080 Ti in the Mac Pro's 4x slot but with a bit of a performance penalty. For more information on the Mac Pro's PCIe slots, see EveryMac's guide and the archived article from developer.apple.com: PCI Product-Specific Details. Bifurcation Later, motherboards, starting with PCIe 3.0, commonly support bifurcation, which allows a PCIe port to be split in half: One 16x port becomes two 8x or in quarters. An 8x PCIe lane card thus can interface by splitting it into two sets of 4x lanes. Bifurcation is mostly used for SSDs, allowing a single PCIe card to host two SSDs. While the Mac Pro can use PCIe expanders (a separate technology for external PCIe slots by harassing the bandwidth of a single PCIe slot), it doesn't support bifurcation. There are PCIe cards that can host more than two M.2 NVMe SSDs without bifurcation, but they require specialized controller chipsets. The result is that multi-drive M.2 PCIe cards that are Mac Pro compatible cost more. This is also discussed in the PCIe NVMe sleds/blades section. For a list of m.2 cards that support multiple NVMe drives, see the M.2 SSD hosts (sleds) section. PCIe Power By default, PCIe provides power via motherboard PCIe slot, up to 75w via 4-pin cables. The power requirements have increased for high-performance GPUs, going past PCIe initial design. To combat the power delivery problem, PCIe cards started coming with additional power ports and increased pins to carry more power. Generally, in PCs, additional power is drawn directly from 12v taps off the power supply that the user can configure. On the Mac Pros, there are two power ports located on the motherboard that can be tapped for additional power. This design choice means less cable mess but also requires buying special mini-PCIe to PCIe cables. Apple's implementation of the PCIe power ports also is non-standard, allowing for more power-draw than required by the PCIe standard. Many PC power supplies also use similar configurations, so that 6 to 8-pin adapters can be used. MacProUpgrade members like Brennan F. and MacRumors members have demonstrated that the Mac Pro using various techniques can deliver roughly 120w and using 4-pin to 6-pin adapters, just shy of the more common 150w with 6-pin cabling. If a PCIe card draws more power than the PCIe power can provide, it will trigger the Mac Pro to shut down instantly. This scenario is generally limited to GPUs with exceptionally high power requirements. The Mac Pro PSU can be modified to deliver more power to the PCIe power taps using modifications such as the Pixlas PSU Mod, allowing the Mac Pro to use high power GPUs, providing the expected 150w safely. PCIe 2.0 vs. 3.0 vs 4.0 and its impact on GPU performance In computer parlance, the idea of bottlenecking is when a computer system is limited by a single component. For whatever reason, there's an incorrect belief that modern GPUs require the bandwidth of a 16x PCIe 3.0 slot or would greatly benefit by using PCIe 4.0. This myth is persistent and wide, despite a lot of information that clearly demonstrates otherwise. When benchmarked in the real-world using an 8x vs. 16x PCIe 3.0 slot, the impact is minimal, pugetsystems.com performed this very test, and it comes out to be roughly 3%-4% impact. An 8x PCIe 3.0 slot has the same bandwidth as a 16x PCIe 2.0 slot. Another common misconception is the Mac Pro's CPUs/bus isn't fast enough to benefit from a high-end GPU, which is patently false. Notably, when it comes to graphics performance, the Mac Pro 2010/2012 remains a performance monster, in most tests besting the iMac Pro running a VII. It may not be as fast as a modern gaming PC running a VII, but depending on the tasks (especially GPU compute), it'll be only 1%-4% slower. More interestingly, when an AMD Radeon 5700 XT was tested in PCIe 2.0 vs 3.0 vs 4.0, TechPowerup after many tests found a 2% average performance difference between PCIe 2.0 and PCIe 4.0. DigitalCitizen found similar results by comparing PCIe 3.0 to 4.0. GPUs are not nearly as bandwidth-intensive as most people assume, (other hardware like SSDs can easily saturate a PCIe bus). I'll give another example, if "bottlenecking" existed in a sense most people visualize it, performance would be capped by bandwidth. Thunderbolt 3, which is also even more bandwidth constricted than PCIe 2.0 16x slots, still finds improvements running a Radeon VII in a Thunderbolt 3 case over less powerful GPUs, including an iMac's own internal AMD Vega 64. The performance is more realized though when adequate bandwidth is available as opposed to a brick wall limitation. Also, in gaming, at high resolutions, the Mac Pro will be nearly as fast as a modern PC. At lower resolutions where the GPU can achieve extreme framerates, the number of calculations per second increases for the CPU to process the necessary data per frame. 240 FPS means the CPU has more data to process per second than if a game was running at 60 FPS, regardless of the resolution. At higher resolutions, the frame rate goes down as the GPU becomes the limiter. The Mac Pro makes a fine 4k gaming machine if one desires to invest in a Vega series GPU or better and is willing to boot Windows 10. When users complain about the lack of PCIe 4.0 on the 2019 Mac Pro, currently, GPUs are not hindered by PCIe 3.0 in any meaningful way... for now.

Delidding CPUs

Delidding is the process of removing the integrated heat spreader (silver cover) on a CPU, that serves as a heat spreader and replacing it with a different thermal material. This is required for CPUs in the Mac Pro 4.1s due to the heatsinks. There are multiple ways to do this, the steady-hands method is to use a razor to scrape it off the CPU (inexpensive), and the more expensive is to buy a Delid-Die-Mate, (roughly $40 USD).

Microarchitectural Data Sampling (MDS) vulnerabilities

A vulnerability Intel CPUs was discovered, called MDS, which targets hyperthreading (the ability to address two instructions in a single CPU cycle under stress loads). It affects CPUs from 2008+. Intel issued a microcode fix for CPUs designed in 2013 and up, leaving out the classic Mac Pros. Apple has updated Safari to prevent drive-by Javascript attacks. Using general safe browsing habits, makes it not very likely that this exploit will affect users despite very sensational headlines like Wired's Meltdown Redux: Intel flaw lets hackers siphon secrets from millions of PCs. The only way to ensure total safety is to disable Hyper-Threading (a significant performance hit), and Apple issued the article How to enable full mitigation for Microarchitectural Data Sampling (MDS) vulnerabilities.

Benchmarking

CPU benchmarks are useful but always a relativistic endeavor. Rather than get into a discussion about the pros and cons of types of benchmarks, the most popular theoretical benchmarking software, GeekBench 5, was released recently. Most users are used to seeing Geekbench 4 numbers, which are not comparable to GeekBench 5. Geekbench's scoring system always has been tied to other CPUs as its anchor for scoring. Users will notice dramatically smaller benchmark numbers in the latest Geekbench as the new reference point is the Intel Core i3 8100, which earns a score of 1000. This doesn't mean the Mac Pro is performing worse, but rather the baseline has risen. Also, GeekBench 5 removes individual memory tests (which isn't very indicative of the real-world), but is entirely 64-bit only for bigger memory stress tests. The encryption and codec manipulation tests also have been updated to reflect current standards, as well as new tests related to machine learning and map calculations. The full list of changes can be read here: GeekBench: Geekbench 5 is released with all-new tests, modes, and scores.

I/O Upgrades The I/O (Input/Output) is a catch-all umbrella term I'm using for anything that doesn't fall under GPU, SSD interfaces, Wireless or audio PCIe cards such as networking and peripherals interfaces (USB/Firewire/SATA). The Mac Pros can support many more cards than listed here. NewerTech and Sonnet are reliable. Not all cards are equal, some are more performant, in the case of USB 3.0/3.1 offering full-duplex per port instead of shared bandwidth. Also, some non-listed cards have issues. I had an off-brand Inateck PCI-E to USB 3.0, which worked but also caused a reboot loop when trying to shut down. The only way to turn off my Mac Pro was to hold down the power key forcibly. I personally use an SYBA SY-PEX40039 SATA card as my bootable SSD for my Samsung Evo. I've elected not to include USB 2.0 only or Gigabit Ethernet-only or SATA II only cards as all are found natively on all versions of the classic Mac Pros. Note: This is not to be taken as a complete list, but rather a list of known working cards that users have confirmed. If you know of a card that's supported by macOS, please reach out to me. USB 3.0 Sonnet Allegro USB 3.0 / Sonnet Allegro Pro

Inateck KT4004

RocketU 1144D / HighPoint RocketU 1144C

HighPoint RocketU 1144E

CalDigit FASTA-6GU3 Pro (Discontinued)

HighPoint RocketU 1144CM -

Inateck PCI-E to USB 3.0 - (Caused Reboot loop in 2008 Mac Pro)

Sonnet Technologies Tempo Duo PCIe (2x eSATA / 2x USB 3.0) - (discontinued)

Newer Technology MAXPower 2 port eSATA 6/GBs & 2 Port USB 3.0 SATA/eSATA Note: Not all SATA cards are bootable on OS X. Currently, the list is expanding, non-bootable cards will be listed as such. Known bootable cards will be listed as such. If no notes appear, it's because I haven't researched this yet. NewerTech MAXPower PCIe eSATA 6G Controller - Bootable

MAXPower 4-port eSATA 6G PCIe 2.0 - (bootable)

MAXPowereSATA 6G PCIe 2.0 RAID 0/1/5/10

MAXPower RAID mini-SAS 6G-2e2i

Sonnet Technologies Tempo SATA Pro - Bootable

Sonnet Technologies Tempo SATA E2P

Sonnet Technologies Tempo SATA 6Gb/s PCIe 2.0 - (discontinued)

Sonnet Technologies Tempo SATA Pro 6Gb PCIe 2.0 - (discontinued)

SYBA SY-PEX40039 SATA III

HighPoint Rocket 620 2 SATA

ORICO PFU3-4P 3 Port

ATTO ExpressSAS H680 Low-Profile x8-External Port

ATTO ExpressSAS H644 Low-Profile 4-Internal/4-External Port

ATTO ExpressSAS H6F0 16-External Firewire Sonnet Technologies Tango Express Combo FireWire 400/USB 2.0 Card

Sonnet Technologies Allegro FireWire 800 PCIe

Sonnet Technologies Allegro FW400 PCIe - (discontinued) USB 3.1 MAXPower 4-Port USB 3.1 Gen 1

Sonnet Technologies Allegro USB-C

StarTech 4-Port USB 3.1 (10Gbps) Card PEXUSB314A2V

Aukey B01AAETL6Y 2 port USB 3.1

CalDigit FASTA-6GU3 Plus (USB 3.1 / 2x eSATA)

Sonnet Technologies Allegro™ Pro USB 3.1 PCIe

Sonnet Technologies Allegro USB-C 4-Port PCIe Ethernet (10 Gigabit) Sonnet Technologies Presto 10GbE 10GBASE-T

Sonnet Technologies Presto 10GbE SFP+

Sonnet Technologies Presto 10GbE 2-Port - (discontinued)

Small Tree P2E10G-1-T, P2E10G-2-T, P2E10G-4-T 10GbE One-Port / Tw- Port/ Four-Port 10GBase-T

Small Tree P2E10G-2-XR, P3E10G-4-XR, P3E10G-6-XR Two-Port / Four-Port/ Six-Port 10GbE 10G-SFP+

Small Tree P2E10G-1-SR, P2E10G-2-SR, P3E10G-4-SR, P3E10G-6-SR One-Port/ Two-Port / Four-Port / Six-Port 10G-SFP+

Solarflare / Solarstorm Cards (drivers last updated in 2013) - see release notes for supported devices

Chelsio- See Release notes on drivers for supported devices

Solarflare - See Release notes on driers for supported devices Useful Links Macrumors: USB 3.x Cards for classic Mac Pro

TonyMacx86: PCI-e to SATA Controller Card for Mac 10.9.2 (ASM1061 vs. Marvell 88 SE 9215)

SATA 3 & USB 3 cards

Display Upgrades The Mac Pro's display limitations are a factor of graphics cards, what OS you are running, and whatever monitor you can afford or are willing to pay for. 5k and Beyond There are users with 5k displays and Mac Pros, including a user confirming two 5k displays working perfectly fine on his Mac Pro. 10-Bit Color / Color Spacing 10-bit color spacing requires a minimum of 10.12 (although Apple introduced 10 bit in 10.11 for the 5k iMac) and it's support is somewhat hazy as few Apple apps support 10-bit color: (Preview, Photos, Final Cut Pro) and some 3rd party apps. The latest Catalina adds desktop wide HDR color spacing support, whereas Windows has had this feature for years. Older NVidia GPUs with the web drivers will not support 10-bit color, but the latest GPUs do. AMD's GPU Drivers lock out 10-bit on its consumer GPUs (sans the VII), but the Pro varients unlock 10 bit color. Unfortunately, Apple's drivers confusingly report 30-bit (aka 10-bit) color even when non compatible hardware is used. If the GPU can address downsampling 30-bit color spaces to 24-bit, it will report 30 bit color. Many true 10-bit displays will report when they're receiving a 10-bit signal. Under Windows, non-pro AMD GPUs will use 10-bit color in games, whereas 2D operations are still wedged into 8 bit color spaces. Most displays (especially budget) use Frame Rate Control (FRC) to achieve simulated 10-bit. FRC works by parsing the 10-bit color stream, and for colors that fall outside the 8-bit range, cycling between near shades of colors within the 8-bit spectrum. This visually creates a simulated 10-bit experience and improves the perceived gamut. This is acceptable for many purposes, but film editors, colorists, and graphic designers may require the accuracy of true 10-bit color. These come with a much higher price tag. When buying a display, it's also important to consider color-space coverage. Color spaces for the unfamiliar are standards of color ranges that can be represented by a display, projector, or printer setup. Monitors may brag about its color space profile. Not all color spaces are equal, some representing a lot fewer colors than others. The important thing is that sRGB is a dated standard from the 1990s, based on CRTs rather than any clear standard. It severely suffers in the ability to represent shades of green and some blues. Today, Apple prefers DCI P3 for its monitors, a standard that vastly improves the range of colors available to a display (roughly 45% of the human eye can see as opposed to the 35% of sRGB) and designed for digital cinema. Adobe RGB is also similar to P3. Both represent a much wider gamut than sRGB. Selecting monitors based on color spaces can assist you in finding a display that's more suitable for photo editing, color grading, capable of more range in the expression of color, and feels more "Mac-like". The latest macOS Catalina brings HDR color space support finally to the Mac platform for compatible GPUs and displays. Refresh rates: 60 Hz (and above) 4k The Hz of a display measures how many times a second the screen is refreshed, which defines the maximum frames-per-second (FPS) a display can render. A 120 Hz display can render a maximum of 120 FPS. 60 Hz is generally considered the minimum refresh rate for "smooth" User-Interfaces, like mouse tracking, dragging windows, scrolling, etc. As computer hardware has improved, so have refresh rates. FreeSync and G-Sync are technologies that allow for variable refresh rates to improve the visual experience (prevent effects like "tearing"), especially in the realm of gaming. Mac OS currently does not support Freesync/G-Sync. I can attest that enabling Freesync on a Freesync display caused the monitor to stop outputting video in 10.13.x with a GeForce 1060 and a Vega 56. Also, both tonymacx86 and MacRumors forum members have experienced the same sort of issues. The workaround is to disable the G-sync and Freesync if the monitor does not produce any video output. Under Windows 10, FreeSync/G-Sync is supported as the limitation is tied to Mac OS. Depending on setup 4k @ 60 Hz+ via HDMI may require workarounds, whereas DisplayPort tends to be far more reliable. I've personally used several 4k displays with my Mac Pro at 60 Hz via DisplayPort with no issues beyond Freesync. Forum members at MacRumors have confirmed that 144 Hz 4k displays do work. There's a minor caveat that flashed 7950s and 7970s booting with 60 Hz 4k displays will hang, thus must run at 30 Hz at the boot screen. Most 79xx cards have dual ROM, so day-to-day, the UEFI ROM can function as the card's default, which bypasses the boot-screen video output. Later GPUs, do not have this issue. Dual-Link DVI Displays & Modern GPUs

(and the 30-inch Cinema Display) Many modern GPUs do not have DVI ports, and many older monitors use DVI. Buying an HDMI -> DVI or DisplayPort -> DVI cable should work, right? Not so fast. If the monitor's resolution is over 1920 x 1200 @ 60 Hz, you will need an active Dual-Link DVI convertor. DVI has always been a bit of a hodge-podge standard, owing to the era it came from when displays were mostly analog. There are multiple variants, DVI-A (analog only), DVI-I (analog or digital), and DVI-D (Digital). To add to the confusion, there's also Dual-Link DVI, which doubles the cable serial links (using the pin-outs) in the cable to effectively double the bandwidth for DVI-D signals, allowing for 1080p @ 120 Hz/2560 × 1600 (or 2560 × 1440) @ 60 Hz/3,840 × 2,400 @ 30 Hz). Because of the data rate limitations of DVI-D, the industry has primarily shifted to the newer DisplayPort and High-Speed HDMI. Both support 8k resolutions at their current iterations, as well as audio. Modern GPUs often do not have DVI connections and only have HDMI and DisplayPort. However, because of the pin-out shenanigans and also bitstream differences, using DVI-D displays (any display that allows for the resolutions listed above) requires an Active Dual-Link DVI to DisplayPort Adapter/Conversion. The converters need additional power, thus usually have a USB connector to draw power. Otherwise, DVI to DisplayPort or HDMI is limited to 1080p @ 60 Hz. This means the ever-popular 30-inch Apple Cinema Display with many modern GPUs will require the active conversion, which often costs north of $120 USD for decent quality ones. If you are wondering, "What about HDMI to Dual-Link DVI"? There isn't any solution as no such device exists on the market. Why you can go HDMI to DisplayPort but not the inverse There are plenty of HDMI -> DisplayPort cables on the market, but they will not work going DisplayPort -> HDMI. HDMI was developed directly as a follow-up to DVI, whereas DisplayPort is a different beast. HDMI and DVI are both based on TMDS (Transition-Minimized Differential Signaling) for data transfer at 5V. Thus a DVI and HDMI cable could be used interchangeably. DisplayPort is entirely different, running its LVDS signal protocol instead and at 3.3v. This is where things get a little more confusing, DisplayPort was later adapted to carry the 5V TMDS called DisplayPort Dual-Mode, but became so ubiquitous that most manufacturers don't even bother to list it. It can pretty much be assumed that any device with a DisplayPort manufactured in the last decade can accept video from an HDMI source. As mentioned above, DisplayPort requires active conversion to carry the Dual-Link DVI signal. DisplayPort also, like HDMI, can carry audio. It also can do more than that and even can transmit bi-directional USB data. HDMI has no such mode to carry LVDS video signals and wasn't designed to be as all-encompassing as DisplayPort. Also, respectively, HDMI predates DisplayPort by four years, released in 2002, whereas DisplayPort was released in 2006. The summary is you cannot connect an HDMI Display to a DisplayPort on a GPU without a convertor. Using a 4k TV as a display The short answer is: yes, you can do it. TVs generally require some minor tweaking of the picture, such as enabling overscan correction in macOS. Those looking to use a TV as a full-time monitor should keep a few things in mind. Not all TVs us Chroma 4:4:4 subsampling. Video editors probably are familiar with this concept as not all cameras are 4:4:4 but may not realize nor are all displays. Chroma subsampling refers to pixel clusters and data representation. The Human eye is much more receptive to changes in luminance than color. Thus, video data can be compressed easily by tracking clusters of chroma values and mapping them over pixels of chroma value. This works great for video codecs when the data is at an endpoint where precision isn't as important (a streaming video, for example). TVs in an effort to cut corners often use this in the panels to both improve response times and lower cost, whereas PC displays are almost always 4:4:4 outside of extremely odd-ball instances. With lower Chroma Subsampling, things like text look blurry due to the decreased chroma resolution. Rtings has a great running list of The 6 Best 4k TVs For PC Monitors and pictorial examples of Chroma subsampling. A 60 Hz 4:4:4 Chroma Subsampled 4k 43 inch display suitable for a PC can be had for as low as $230 USD, making them popular for many users. Mac OS supports audio over HDMI as well, see the GPU section for details. Notably, with the increase in size comes a decrease in sharpness. For a monitor, one intends to sit at normal desk-distance, 43 inches is appropriate as it's Pixels Per Inch (PPI) is approximately 102 PPI. For comparison: Apple's 30-inch Cinema display was roughly 101 PPI, it's 27 Inch Cinema Display 109 PPI. Apple's laptops pre-Retina generally were around 110 PPI and its retina laptops at 220 PPI. A 4k 42 inch TV is roughly 105 PPI, making it appropriate as a very large standard definition display. I suggest the PPI calculator for calculating a display's PPI quickly. UI scaling External monitors receive the same UI scaling abilities as found in MacBooks. UI scaling requires Mavericks 10.9.3+, although the GPU may require a later version of Mac OS. Some 4k displays will not report all scaled resolutions. To display all the scaled resolution options: Open preferences and click the Displays If the option "Default for display" is selected, option-click Scaled If Scaled is already selected, option-click "Scaled." Does my GPU support 4k? This is where Google is your friend, search your GPU's model and max resolution (GPU model can be found the About This Mac section). That said, there's another way to check, too: If your GPU does not have HDMI or Display Port, it cannot output 4k, as Dual-Link DVI maxes out at 2560 x 1600. That said, an HDMI port and/or DisplayPort does not guarantee 4k support but makes it simply a possibility. Control Brightness on a 3rd Party Display Some displays use software to control the brightness, a kind MacRumors member wrote a utility to assist for those displays. Apple 27-inch Thunderbolt Display

(and the 27-inch LED Cinema Display) Apple made two 27-inch displays, the LED Cinema Display, and the Thunderbolt Display. Both look very similar and thus cause a lot of confusion as they are frequently mislabeled. The LED model uses mini DisplayPort and has the model number A1316. It can be connected via an adapter from HDMI to mini-DisplayPort port or DisplayPort to mini-DisplayPort, however, it is less common than it's successor. The Apple Thunderbolt Display, often incorrectly referred to as the "Thunderbolt Cinema Display" (technically it is not part of the Cinema display line) is a poor choice for Mac Pros because it does not use mini-displayport but rather uses Thunderbolt (despite the connector looking the same as its predecessor). You cannot use any adapter to make the Thunderbolt display backward compatible to other technologies (HDMI, DisplayPort, DVI). On the backside of the display, the Thunderbolt display has multiple ports: three USB 2.0 ports, single Firewire 800 port, and a single Gigabit Ethernet port, whereas the LED Display only has USB 2.0 Ports. The Mac Pro, by default, is not equipped with Thunderbolt. Yet a MacProUpgrade user using an ASUS Expansion Card for Z170 & X99 Motherboards ThunderboltEX 3 to enable video pass-through, from his GPU. This isn't recommended as the computer will not wake from sleep and remains experimental. Currently, there is progress with Thunderbolt 3 cards. Recommended Places to go for Monitor Recommendations The wonderful thing about monitors is the large variety, but it can make it daunting to select one. I'm personally a fan of the following sites: Rtings, PCmag, Wirecutter, Consumer Reports, Tomshardware, Digital Trends, as all sites do actual hands-on reviews as opposed to listicles of dubious rapport. I ended up with a BenQ PD3220u as it's a true 10-bit 4k panel that has a wide gamut, supporting 95% of the P3 color profile after trying several lesser displays.

Audio Every iteration of the Mac Pro comes with a front-facing headphone Analog Output, a back-facing analog output, a back-facing line-in analog input, and S/PDIF (Sony/Phillips Digital Interface) I/O in the form of two Optical (Toslink). It is capable of transmitting audio via both USB and Firewire interfaces (and even Thunderbolt 3). The Mac Pro's internal hardware is limited to a maximum of 24-bit sound, and 96 kHz (Mac Pro 4.1, 5.1) via the analog output and 96 kHz, 24 PCM audio bit via the SPDIF interface. With various audio interfaces, the Mac Pro can support many, many channels of high-resolution audio, commonly tapping out at 24-bit, 192 Khz. A sound's bit-depth and sample rate (resolution) are analogous to a graphic file's bit-depth and resolution. Surround Sound and High-resolution audio The short answer is the Mac Pro can output multichannel audio but only passthrough popular surround sound used for movies (Dobly Digital, DTS, AAC) codecs via applications like VLC. It cannot output games in surround sound in Mac OS. This isn't a hardware limitation unique to the Mac Pros but rather software. In Windows, the Mac Pro fairs better for surround sound. Also, the Mac Pro's ability to output 96 kHz 24-bit sound via the analog output is a bit dubious, but it can play back high-resolution media without specialized hardware. Whether via the analog outputs is noticeable is questionable. To explain the above adequately (analog outputs, surround sound, etc.), I've elected to hide by default as the long answer is long: Click to show long answer for Understanding Audio and codecs Uncompressed digital audio almost entirely exists as PCM (Pulse-code modulation) which describes audio by checking a soundwave's pressure by a set number of times a second. Each time it is checked is referred to as a sample.hTus the rate of how many times the sound's pressure is checked is the sample rate and is expressed in hertz. 1 Hz = 1 second. 1 khz = 1/1000 of a second. According to the Nyquist–Shannon sampling theorem: To capture a sound frequency, the minimum sample rate must be double that of the sound frequency to get both its peak and valley. The human ear can hear 20 Hz to 20 kHz as a general rule although this changes as one gets older or damaged, so generally audio formats top out at 44.1 khz or 48 khz (Vinyl can go as high as 45 kHz but due to the ultrasonic vibrations interfering with the prints, are mostly capped to 22 Khz- 23 Khz). Some audiophiles/audio engineers argue the extra sound outside of human hearing affects the audible range as it creates phasing and modulation known as "overtones." For each sample, the level of sound pressure is recorded as a simple numerical value. Depending on how many bits are assigned to the sound file determines the maximum dynamic range. The maximum dynamic range can be determined using the signal-to-quantization-noise ratio. A 16-bit audio file can describe approximately 96 dB between no sound to its loudest sound. 24-bit audio can describe 144 dB of dynamic range (a NASA rocket launch is roughly 140 dB and can instantly produce severe irreversible hearing damage, a vinyl record being analog has roughly 80 dB of dynamic range). Thus even the best digital-to-analog converters and the best analog-to-digital converters are in reality, unable to make full use of the 24-bit dynamic range. That said, even a piece of hardware able to capture a dynamic range of 107 dB (17 bits of worth dynamic range) is still 2x the number of levels in sound pressure. Thus a 96 khz / 24-bit audio file describes audio well beyond the capabilities of human hearing and captures overtones of instruments. I created a simple Audio bit-depth calculator that can be used to calculate data rates, dynamic ranges, and so forth. The Mac Pro when measured, was only able to output 91 dB with a 75 Ohm load, which is slightly below 16-bit (unsurprising). There's little be gained by playing back 24-bit audio via the analog output, and the front output is faired worse than an iPod. This isn't to say high-resolution audio isn't useful, but rather without additional hardware, the Mac Pro will see little gains when trying to play back 24-bit sound. That said there are many external audio solutions like USB headphone amps to dedicated digital-to-analog converters that can be had at many price ranges that are more performant. I imagine one of the factors for the long-rumored Apple Music, enabling high-resolution audio is simply that its current hardware would barely benefit if it does at all. Lossless audio would be far more beneficial than high-rez audio. Storing PCM audio isn't very space-intensive today (a 12 TB drive could store 18,460+ uncompressed Audio CDs), but once upon a time, a CD carried an incredible amount of data and processing PCM audio was a considerable task for a computer. )Note: There are other obscure PCM alternatives like DSD but generally not hardware supported thus converted to PCM.) Most people understand that MP3s and AAC are lossy audio codecs at this day in age, akin to most video codecs. Codecs are complex algorithms used to compress down specifically data-streams to save space and/or bandwidth. Not all codecs are equal, often must balance CPU usage to decode, how effective they are at varying levels of compression, and so forth. Thus, codecs arouse to make both video and audio more easily distributed and still aid in storage and distribution (streaming). More channels of audio meant more data to store thus codecs arose to tackle that issue, starting in 1992 with AC3 by Dobly for movies. Today, Blu-Ray movies use lossless codecs (codecs designed to save space but output a byte-for-byte accurate reproduction of the original bitstream) made by both Dolby and DTS and videogame consoles can skip codecs altogether with HDMI and output RAW PCM steams for surround sound, as the sounds are being generated/played back/manipulated in realtime. The S/PDIF is simply a unidirectional data port that dates back to AES3, it's professional cousin and was designed with 2-channel audio in mind, and thus was limited to 2-Channel PCM audio. However, being a data-port, it supported the ability to send other bitstreams. Using codecs that converted discrete multichannel audio into a single bitstream, a SPDIF port could transmit encoded multichannel audio like Dolby Digital (AC3) and DTS and thus became the default standard digital formats like CD Players, and DVD players for home theaters, with the catch that the compressed audio needed a decoder to convert the bitstream back to multichannel audio. Over time, this evolved as CPUs and specialized chipsets improved so that game consoles like the PS2 and Xbox (and following consoles like the PS2 and Xbox 360) could encode in real-time multichannel audio from a game into Dolby Digital (and in later consoles DTS) to be sent via the SPDIF data port, and then decoded by a Home Theater Receiver or all-in-one speaker set into surround sound. PCs were able to support multichannel audio before game consoles, using audio cards but lacking the specialized hardware and/or foresight only outputted audio as analog (usually requiring three stereo cables to carry the 6 channels for 5.1 sounds) and later acquired the ability to convert discrete channels to popular codecs using technologies like Dolby Digital Live. Unfortunately, OS X/Mac OS's CoreAudio supports thousands of simultaneous audio streams that can be mapped to hardware inputs and outputs and thus can be used to playback multichannel audio with one major catch: It cannot convert multichannel audio in realtime to any popular multichannel audio codec nor can it decode any popular codec in realtime to multichannel outputs. OpenAL (an open alternative to EAX and DirectSound) was brought over to Mac OS 9 but failed to be embraced with a very ill-fated SoundBlaster Live card and later the M-Audio Revolution 7.1. Thus without a guiding force from Apple, Mac OS has never had consumer applications that supported more than stereo in real-time. However, media players like VLC can output the bitstreams from media via the SPDIF port found the Mac Pro. Even with technologies like HDMI which, are extremely bandwidth-heavy, Apple still hasn't embraced a surround sound that could be used for Mac gaming. Ironically, Mac OS can be used to master a 7.2 soundtrack for a blockbuster movie but would not easily play it back once encoded. Speakers, headphones and more Most likely, you will not be using the internal speaker in the Mac Pro other than to hear the startup chime. Audio output is very free form when it comes to computers as they play nicely with analog and digital hardware. There's any number of routes to go, from inexpensive computer speakers, studio monitors, home theater receivers with esoteric audiophile brands. For most consumer applications, there's not much reason to use any dedicated computer hardware as digital out is digital out. Audio can be outputted via the analog outputs, SPDIF, Firewire, USB, HDMI (GPU dependent), DisplayPort (GPU dependent), and Bluetooth out-of-the-box. Other formats can be added via upgrades. Prosumer/Professional Audio Professional hardware is less of a grab bag than consumer audio as Mac OS has a very long and proud history as the defacto choice for studios, audio engineers and musicians. CoreAudio supports low-latency multichannel audio interfaces without any specialized drivers. For most audio interfaces, the basic functionality works out of the box. That said, audio-interfaces come in various formats, like PCIe Cards, USB, Firewire, and Thunderbolt, and additional functionality can be tied to both the drivers and compatible software. CoreAudio allows device aggregation, which will map multiple pieces of hardware to appear to software applications as a single device, making it easier to assign inputs and outputs to a software application. Listing compatible hardware would be a losing game for this guide as there are decades worth of compatible gear. Most USB audio interfaces are HID-compliant, meaning even cheapo-USB audio boxes designed for Windows generally are compatible on a fundamental level with Mac OS. However, if they rely on additional drivers, they may not work with Mac OS. It's best to do your research. Hardware makers like Ableton, AKIA, Apogee, Behringer, Focusrite, IK, Korg, Line, MOTU, Native Instruments, Numark, Presonus, RME, Steinberg Tascam, Universal Audio, Yamaha make almost exclusively hardware compatible for both Mac OS and Windows (not one or the other). There's plenty more I didn't list, again I must stress doing your homework. Most likely, the piece of PC audio gear you have your eyes on is Mac compatible. CoreAudio also supports by default Midi, which can be done via Midi interfaces or via USB. For general midi devices, no specialized drivers are needed, but often additional drivers are needed for extended functionality like saving presets or configuration settings (it's worth noting some devices can also use esoteric midi commands to perform these same settings as well). Overall, the Mac Pro is a very capable audio workstation and more than capable of professional work even today. That said, as audio applications become more advanced/complicated/full-featured/robust as do the CPU requirements. Your mileage will inevitably depend on the number of software instruments/synths/effects and their combined requirements, but audio software has a much lower bar for hardware requirements than video. Lastly, the Mac Pro 3.1s and below do not support SSE 4.2 CPU instructions. I have personally encountered with Serato DJ that an 8-core 2.8 GHz Mac Pro 3.1 with 20 GB would often display buggy behavior and latency, whereas even a modest 2013 quad-core i5 MacBook Pro with 8 GBs of RAM and a Mac Pro 5.1 had absolutely zero problems running this software. I wouldn't be surprised if other software suffers under older Mac Pros as well, although Logic, Cubase, and Ableton all ran adequately on a 3.1 Mac Pro. Audio over HDMI See the GPU section of this guide. Audio over Thunderbolt See the Thunderbolt section of this guide.

Enabling Handoff/Continuity

The Mac Pros for Handoff/Continuity require using the Continuity-Activation-Tool to enable it once the hardware requirements have been met. The Mac Pro 1.1/2.1s cannot use Handoff/Continuity due to OS limitations.

Mac Pro 3.1 requires BCM94360CD (Airport Extreme)

Mac Pro 4.1/5.1 requires Bluetooth Adapter + original wifi Chipset OR BCM94360CD (Airport Extreme).

Source for above: Continuity-Activation-Tool

Enabling Nightshift on Mac Pros

Sometimes hardware support is entirely arbitrary as in the case of Nightshift. Nightshift can be enabled in 10.14+ Mojave using a nifty script written by a community member.

Enabling Apple Watch Auto Unlock with the Mac Pro

Officially Apple does not support classic Mac Pros for Apple Watch Auto Unlock. Of course, enterprising users have figured out how to enable it, but it requires disabling SIP and a few terminal commands. Notably, you'll need a Mojave compatible Airport card.

How to Update the Recovery Partition in High Sierra on unsupported Macs / fix security Updates

High Sierra Security Updates will often fail on unsupported Macs as they require updates to the Recovery Partition. Luckily, MacRumors readers have concocted a script to automate this process.

Multi-OS USB Bootable Flash Drives

Recently in the Mac Pro forums, a user linked a "Five in one" USB solution that includes five versions of macOS on a single USB. These can be easily created by users following the directions from Apple, How to create a bootable installer for macOS. The only difference is the user first must divide the USB flash drive into multiple partitions (large enough for the Mac OS installers), which Apple also provides Partition a physical disk using Disk Utility on Mac.

Upgrading from a single CPU to dual CPU on a 2009 - 2012

It is possible to upgrade any 4,1/5,1 from a single CPU to dual CPU, but this requires a dual CPU tray, which is uncommon and often cost as much as an entire used Mac Pro. They occasionally do pop-up when someone parts out a non-functional Mac Pro.

Notably, you cannot use the trays from Mac Pro 5.1 in a 4.1 even if the Mac Pro is flashed to 5.1. When 4.1 is flashed to 5.1, the tray and backplane SMC are not updated and stay at 1.39f5. The 2010-2012 are at version 1.39f11. Trying to use a tray using a different SMC than the backplane confuses the fans, causing them to go into full leaf blower mode.

You cannot swap CPU trays from 4.1 (2009) Mac Pros with 5.1 (2010-2012).