Corsair’s Neutron Series is developing a habit of introducing us to new SSD controllers. The initial members of the family were the first consumer-oriented drives to feature Link_A_Media Devices’ LM87800, a good all-around performer that’s particularly adept at handling more demanding workloads. Today, the new Neutron Series XT provides our first look at Phison’s latest PS3110-S10 controller.

Like LAMD, Phison isn’t exactly a household name. The Taiwanese firm has been around for ages, though, and its previous PS3108 controller can be found in several value-oriented SATA SSDs, including Corsair’s Force Series LS. The PS3110 adds more horsepower along with enterprise-friendly features intended to push Phison into the realm of high-end PCs and entry-level servers.

Phison’s ambitions aren’t lost on Corsair, which says the Neutron Series XT was “designed for the absolute best in class performance” for a SATA SSD. Since we’ve tested pretty much every high-performance SATA drive out there, it’s only appropriate that we see how the XT compares.

Quad cores meet A19 NAND

Like just about every other SSD controller, the PS3110 has a 6Gbps host link and an eight-channel NAND interface. But unlike its peers, which typically have no more than three processor cores, the chip is a full-blown quad. Three of its four cores are devoted exclusively to flash management chores like background garbage collection. Phison claims this additional horsepower lowers command latencies and helps to improve performance with sustained workloads and when the drive is nearly full.

Consumer drives are often filled close to capacity, but the associated workloads are usually very bursty in nature. Sustained I/O is typically confined to servers, where some of the controller’s other perks should be appreciated. The PS3110 boasts end-to-end data protection that performs error detection correction between the drive’s controller, DRAM cache, and NAND storage. The controller also has a Smart ECC scheme that uses RAID-like parity to recover from uncorrectable errors caused by flash failures.

Phison’s SmartFlush feature aggressively pushes in-flight data to the flash in order to minimize the chance of data loss due to unexpected power failures. The Neutron Series XT doesn’t appear to have capacitors devoted to keeping the lights on, though. Consumer-oriented SSDs like this one rarely feature robust power-loss protection.

256-bit AES encryption support is pretty common even on consumer-grade drives, and the PS3110’s implementation is compliant with the TCG Opal 2.0 spec. Unfortunately, the spec sheet doesn’t mention the IEEE 1667 credentials required by Microsoft’s eDrive standard.

On the flash front, the PS3110 supports the current generation of “1y” nanometer NAND along with next-gen chips fabbed with “1z” tech. The controller can address the NAND in MLC or TLC mode, which is a notable change from the MLC and SLC configs available with Phison’s previous SSD controller. Trading SLC for TLC makes a lot of sense for consumer-grade drives. Swapping one bit for three also has some appeal for entry-level servers, since those machines are unlikely to require ultra-high-endurance flash. In fact, Samsung is already selling budget server SSDs with TLC NAND.

In the Neutron Series XT, the Phison controller is paired with the “A19” variant of Toshiba’s 19-nm MLC NAND. SSDs generally use the same NAND throughout the line, but the XT employs different die sizes depending on the total capacity. The 240GB and 480GB variants sport 8GB chips, while the 960GB flagship has larger 16GB ones.

Having more, smaller dies is preferable in lower-capacity SSDs because it allows the controller to flex more of its internal parallelism. Most SSD controllers require at least 32 dies to achieve peak performance, and at 8GB per die, even the XT 240GB has sufficient NAND to hit top speed. Corsair’s “internal performance metrics” suggest the base model should have no problem keeping up with its larger siblings.

Capacity Die config Max sequential (MB/s) Max 4KB random (MB/s) Endurance (TBW) Read Write Read Write 240GB 32 x 8GB 564 547 391 378 124TB 480GB 64 x 8GB 562 542 404 361 124TB 960GB 64 x 16GB 562 532 384 357 124TB

Corsair doesn’t list random 4KB IOps for each capacity, but it does indicate that the family hits “up to” 100k IOps with reads and 90k IOps with writes. You can work backwards from the MB/s totals to get the number of 4KB IOps.

I’ll do the math for the endurance spec: the Neutron Series XT is rated for 124TB of total writes, which works out to 70GB per day for the length of the five-year warranty. The terabyte total is fairly generous, and the five-year coverage matches the warranty attached to Corsair’s other Neutron SSDs. (Corsair initially indicated that the XT had a three-year warranty, but the company has since clarified that the coverage lasts for five years.)

Users can monitor drive wear by checking the SMART attributes with third-party software or Corsair’s own SSD Toolbox utility. In addition to providing an overall health rating, the attributes track bad blocks, host writes, and both program and erase errors. Too bad there’s no decoder ring for the vague “vendor specific” variables.

The Toolbox utility performs other functions, such as applying firmware updates, cloning drive contents, optimizing Windows settings, and completing secure erase procedures. It’s not the fanciest SSD software around, but it’s unobtrusive, and it covers all the important bases.

Before we dive into our performance results, I have to take a moment to highlight a somewhat mundane detail. But there’s a certain elegance to the XT’s two-piece chassis, which sandwiches the drive without a single screw. Even with the top popped off, the circuit board is held in place by little nubbins that poke in from the sides.

The simplified clamshell is surely a cost-cutting measure, as is the stubby circuit board that sits inside. Given the extremely price-competitive nature of the consumer SSD market, it’s easy to see why Corsair might want to shave pennies wherever it can—not that there’s anything wrong with that. The case still feels solid, and the brilliant red paint adds a dash of ‘zazz.

CrystalDiskMark — transfer rates

TR regulars will notice that we’ve trimmed a few tests from our usual suite of storage results. The drives were all benchmarked in the same way, but we’ve excluded the results for tests that have grown problematic or less relevant over time. This abbreviated format should be a little easier to digest until we put the finishing touches on our next-gen storage suite, which is nearly complete.

First, we’ll tackle sequential performance with CrystalDiskMark. This test runs on partitioned drives with the benchmark’s default 1GB transfer size and randomized data.

We’ve color-coded the results to make the Neutron Series XT 240GB—and the other Corsair SSDs—easier to pick out of the pack. We’ve also colored the Force Series LS in a different shade to provide a handy reference point for Phison’s older PS3108 controller. The LS 240GB has a 16 x 16GB die config, so keep in mind that it’s at a considerable disadvantage versus the XT 240GB, which has twice as many NAND dies.

The Neutron Series XT aces our sequential throughput tests, beating even Samsung’s top-of-the-line 850 Pro. The XT enjoys a comfortable edge over its GTX sibling in both tests, and it has a substantial advantage over the Force Series LS with writes.

HD Tune — random access times

Next, we’ll turn our attention to random access times. We used HD Tune to measure access times across multiple transfer sizes. SSDs have near-instantaneous seek times, so it’s hard to graph the results on the same scale as mechanical drives. The WD Black and Seagate SSHD will sit out this round to focus our attention on the SSDs.

Although the XT’s access times with 4KB random I/O are relatively low, the results with 1MB transfers are mixed. The drive has the quickest response time with larger writes but is surprisingly sluggish with reads. We also run HD Tune’s 512-byte and 64KB random I/O tests, but the XT doesn’t exhibit any slowness with those transfer sizes.

TR FileBench — Real-world copy speeds

FileBench, which was concocted by TR’s resident developer Bruno “morphine” Ferreira, runs through a series of file copy operations using Windows 7’s xcopy command. Using xcopy produces nearly identical copy speeds to dragging and dropping files using the Windows GUI, so our results should be representative of typical real-world performance. We tested using the following five file sets—note the differences in average file sizes and their compressibility. We evaluated the compressibility of each file set by comparing its size before and after being run through 7-Zip’s “ultra” compression scheme.

Number of files Average file size Total size Compressibility Movie 6 701MB 4.1GB 0.5% RAW 101 23.6MB 2.32GB 3.2% MP3 549 6.48MB 3.47GB 0.5% TR 26,767 64.6KB 1.7GB 53% Mozilla 22,696 39.4KB 923MB 91%

The names of most of the file sets are self-explanatory. The Mozilla set is made up of all the files necessary to compile the browser, while the TR set includes years worth of the images, HTML files, and spreadsheets behind my reviews. Those two sets contain much larger numbers of smaller files than the other three. They’re also the most amenable to compression.

To get a sense of how aggressively each SSD reclaims flash pages tagged by the TRIM command, the SSDs are tested in a simulated used state after crunching IOMeter’s workstation access pattern for 30 minutes. The drives are also tested in a factory fresh state, right after a secure erase, to see if there is any discrepancy between the two states. There wasn’t much of one with the Force Series XT, so we’re only presenting the used-state scores.

The Neutron Series XT doesn’t have the fastest copy speeds in FileBench. It’s not far off the overall lead in the RAW test, though, and it’s fairly competitive when copying movies and MP3s. The drive doesn’t fare as well in the Mozilla and TR tests, which have much higher numbers of much smaller files.

There’s no contest between the XT and Corsair’s other Phison-based contender. The Force Series LS is among the slowest SSDs across the board, and it’s especially hopeless when copying smaller files. These results don’t provide any insight on whether the drive’s poor showing is an artifact of the older Phison controller or the less-than-ideal NAND configuration, but both factors likely play a role.

TR DriveBench 2.0 — Disk-intensive multitasking

DriveBench 2.0 is a trace-based test comprised of nearly two weeks of typical desktop activity peppered with intense multitasking loads. More details on are available on this page of our last major SSD round-up.

We measure DriveBench performance by analyzing service times—the amount of time it takes drives to complete I/O requests. Those results are split into reads and writes.

Our mean service time metrics suggests the Neutron Series XT is very responsive with real-world I/O. Indeed, the XT has one of the quickest read service times we’ve ever measured in DriveBench. That’s a stark contrast to the Force Series LS, which has by far the slowest service times with both reads and writes. The LS has an even higher mean write service time than the mechanical drives.

All the SSDs execute the vast majority of DriveBench requests in one millisecond or less—too little time for end users to perceive. We can also sort out the number of service times longer than 100 milliseconds, which is far more interesting data. These extremely long service times make up only a fraction of the overall total, but they’re much more likely to be noticeable.

Although the Neutron Series XT doesn’t suffer too many extremely long reads, it does exhibit more sluggish writes than most of the competition, including its GTX kin. The Neutron Series GTX logs just a single write service time over 100 milliseconds, compared to over ten thousand for the XT. At least the XT is in much better shape than the Force Series LS, which trades blows with the Crucial M500 at the very back of the field.

IOMeter

Our IOMeter workload features a ramping number of concurrent I/O requests. Most desktop systems will only have a few requests in flight at any given time (87% of DriveBench 2.0 requests have a queue depth of four or less). We’ve extended our scaling up to 32 concurrent requests to reach the depth of the Native Command Queuing pipeline associated with the Serial ATA specification. Ramping up the number of requests also gives us a sense of how the drives might perform in more demanding enterprise environments.

We run our IOMeter test using the fully randomized data pattern, which presents a particular challenge for SandForce’s write compression scheme. We’d rather measure SSD performance in this worst-case scenario than using easily compressible data.

There’s too much data to show clearly on a single graph, so we’ve split the results. You can compare the Neutron Series XT’s performance to that of the competition by clicking the buttons below each graph.

Instead of presenting the results of multiple access patterns, we’re concentrating on IOMeter’s database test. This access pattern has a mix of read and write requests, and it’s similar to the file server and workstation tests. The results for these three access patterns are usually pretty similar. We also run IOMeter’s web server access pattern as part of our standard suite of tests, but it’s made up exclusively of read requests, so the results aren’t as applicable to real-world scenarios. Our own web servers log a fair amount of writes, for example.





Phison might want to rethink its server plans for the PS3110 controller. The Neutron Series XT’s I/O rate plateaus after only a few concurrent requests, making the drive ill-suited to extremely demanding workloads. Several of the other SSDs, including the Neutron Series GTX, deliver much higher I/O rates as the load scales up.

Again, though, it’s worth pointing out that the XT is a huge improvement over the Force Series LS. The LS delivers fewer IOps at its peak than the XT does at its worst.

Boot duration

Before timing a couple of real-world applications, we first have to load the OS. We can measure how long that takes by checking the Windows 7 boot duration using the operating system’s performance-monitoring tools. This is actually the first test in which we’re booting Windows off each drive; up until this point, our testing has been hosted by an OS housed on a separate system drive.

Level load times

Modern games lack built-in timing tests to measure level loads, so we busted out a stopwatch with a couple of titles.

All the SSDs are within about a second of each other in our load-time tests, making the differences between them difficult to discern. Even the Force Series LS loads the OS and games about as quickly as the other drives.

We’re putting the finishing touches on an all-new storage suite with a collection of fresh load-time tests. Thanks to everyone for their suggestions.

Power consumption

We tested power consumption under load with IOMeter’s workstation access pattern chewing through 32 concurrent I/O requests. Idle power consumption was probed one minute after processing Windows 7’s idle tasks on an empty desktop.

The Neutron Series XT is somewhat power-hungry under load but quite frugal at idle. It’s important to keep in mind that the IOMeter numbers come from a much heavier load than is typical for client systems. I wouldn’t worry about the XT burning through a notebook’s battery life.

For what it’s worth, the Force Series LS has the lowest power consumption of the bunch. That doesn’t make up for the drive’s middling performance, but it’s something, I suppose.

That’s it for performance. If you’re curious about the other SSDs in this review or about how we conduct our testing, hit up the methods section on the next page. Otherwise, feel free to skip ahead to the conclusion.

Test notes and methods

Here’s a full rundown of the SSDs we tested, along with their essential characteristics.

Flash controller NAND Adata Premier SP610 512GB Silicon Motion SM2246EN 20-nm Micron sync MLC Adata Premier Pro SP920 512GB Marvell 88SS9189 20-nm Micron sync MLC Corsair Force GT 240GB SandForce SF-2281 25-nm Intel sync MLC Corsair Force LS 240GB Phison PS3108-S8 19-nm Toshiba Toggle MLC Corsair Neutron 240GB LAMD LM87800 25-nm Micron sync MLC Corsair Neutron GTX 240GB LAMD LM87800 26-nm Toshiba Toggle MLC Corsair Neutron XT 240GB Phison PS3110-S10 A19-nm Toshiba Toggle MLC Crucial M500 240GB Marvell 88SS9187 20-nm Micron sync MLC Crucial M500 480GB Marvell 88SS9187 20-nm Micron sync MLC Crucial M500 960GB Marvell 88SS9187 20-nm Micron sync MLC Crucial M550 256GB Marvell 88SS9189 20-nm Micron sync MLC Crucial M550 512GB Marvell 88SS9189 20-nm Micron sync MLC Crucial M550 1TB Marvell 88SS9189 20-nm Micron sync MLC Crucial MX100 256GB Marvell 88SS9189 16-nm Micron sync MLC Crucial MX100 512GB Marvell 88SS9189 16-nm Micron sync MLC Intel 335 Series 240GB SandForce SF-2281 20-nm Intel sync MLC Intel 520 Series 240GB SandForce SF-2281 25-nm Intel sync MLC Intel 730 Series 480GB Intel PC29AS21CA0 20-nm Intel sync MLC OCZ Vertex 4 256GB Indilinx Everest 2 25-nm Micron sync MLC OCZ Vertex 450 256GB Indilinx Barefoot 3 M10 20-nm Micron sync MLC OCZ Vertex 460 240GB Indilinx Barefoot 3 M10 19-nm Toshiba Toggle MLC OCZ ARC 240GB Indilinx Barefoot 3 M10 A19-nm Toshiba Toggle MLC SanDisk Extreme II 240GB Marvell 88SS9187 19-nm SanDisk Toggle SLC/MLC Samsung 840 Series 250GB Samsung MDX 21-nm Samsung Toggle TLC Samsung 840 EVO 250GB Samsung MEX 19-nm Samsung Toggle TLC Samsung 840 EVO 500GB Samsung MEX 19-nm Samsung Toggle TLC Samsung 840 EVO 1TB Samsung MEX 19-nm Samsung Toggle TLC Samsung 840 Pro 256GB Samsung MDX 21-nm Samsung Toggle MLC Samsung 850 Pro 512GB Samsung MEX 32-layer Samsung V-NAND Seagate 600 SSD 240GB LAMD LM87800 19-nm Toshiba Toggle MLC Seagate Desktop SSHD 2TB NA 24-nm Toshiba Toggle SLC/MLC WD Caviar Black 1TB NA NA

The solid-state crowd is augmented by a couple of mechanical drives. WD’s Caviar Black 1TB represents the old-school hard drive camp. Seagate’s Desktop SSHD 2TB is along for the ride, as well. The SSHD combines mechanical platters with 8GB of flash cache, but like the Caviar Black, it’s really not a direct competitor to the SSDs. The mechanical and hybrid drives are meant to provide additional context for our SSD results.

Since you’ve made it this far, here are a couple more shots of the Neutron Series XT:

We used the following system configuration for testing:

Processor Intel Core i5-2500K 3.3GHz CPU cooler Thermaltake Frio Motherboard Asus P8P67 Deluxe Bios revision 1850 Platform hub Intel P67 Express Platform drivers INF update 9.2.0.1030 RST 10.6.0.1022 Memory size 8GB (2 DIMMs) Memory type Corsair Vengeance DDR3 SDRAM at 1333MHz Memory timings 9-9-9-24-1T Audio Realtek ALC892 with 2.62 drivers Graphics Asus EAH6670/DIS/1GD5 1GB with Catalyst 11.7 drivers Hard drives Seagate Desktop SSHD 2TB with CC43 firmware WD Caviar Black 1TB with 05.01D05 firmware Adata Premier SP610 512GB with N0402C firmware Adata Premier Pro SP920 512GB with MU01 firmware Corsair Force Series GT 240GB with 1.3.2 firmware Corsair Force Series LS 240GB with S8FM07.9 firmware Corsair Neutron Series 240GB with M206 firmware Corsair Neutron Series GTX 240GB with M206 firmware Corsair Neutron Series XT 240GB with SAFC00.e firmware Crucial MX100 256GB with MU01 firmware Crucial MX100 512GB with MU01 firmware Crucial M500 240GB with MU03 firmware Crucial M500 480GB with MU03 firmware Crucial M500 960GB with MU03 firmware Crucial M550 256GB with MU01 firmware Crucial M550 1TB with MU01 firmware Intel 335 Series 240GB with 335s firmware Intel 520 Series 240GB with 400i firmware Intel 730 Series 480GB with L2010400 firmware OCZ Vector 150 256GB with 1.1 firmware OCZ Vertex 450 256GB with 1.0 firmware OCZ Vertex 460 240GB with 1.0 firmware OCZ ARC 100 240GB with 1.0 firmware SanDisk Extreme II 240GB with R1131 Samsung 830 Series 256GB with CXM03B1Q firmware Samsung 840 Series 250GB with DXT07B0Q firmware Samsung 840 EVO 250GB with EXT0AB0Q firmware Samsung 840 EVO 500GB with EXT0AB0Q firmware Samsung 840 EVO 1TB with EXT0AB0Q firmware Samsung 840 Pro Series 256GB with DXM04B0Q firmware Samsung 850 Pro 512GB with EXM01B6Q firmware Seagate 600 SSD 240GB with B660 firmware Power supply Corsair Professional Series Gold AX650W OS Windows 7 Ultimate x64

Thanks to Asus for providing the systems’ motherboards and graphics cards, Intel for the CPUs, Corsair for the memory and PSUs, Thermaltake for the CPU coolers, and Western Digital for the Caviar Black 1TB system drives.

We used the following versions of our test applications:

Some further notes on our test methods:

To ensure consistent and repeatable results, the SSDs were secure-erased before almost every component of our test suite. Some of our tests then put the SSDs into a used state before the workload begins, which better exposes each drive’s long-term performance characteristics. In other tests, like DriveBench and FileBench, we induce a used state before testing. In all cases, the SSDs were in the same state before each test, ensuring an even playing field. The performance of mechanical hard drives is much more consistent between factory fresh and used states, so we skipped wiping the HDDs before each test—mechanical drives take forever to secure erase.

We run all our tests at least three times and report the median of the results. We’ve found IOMeter performance can fall off with SSDs after the first couple of runs, so we use five runs for solid-state drives and throw out the first two.

Steps have been taken to ensure that Sandy Bridge’s power-saving features don’t taint any of our results. All of the CPU’s low-power states have been disabled, effectively pegging the 2500K at 3.3GHz. Transitioning in and out of different power states can affect the performance of storage benchmarks, especially when dealing with short burst transfers.

The test systems’ Windows desktop was set at 1280×1024 in 32-bit color at a 75Hz screen refresh rate. Most of the tests and methods we employed are publicly available and reproducible. If you have questions about our methods, hit our forums to talk with us about them.