When Micron introduced its M600 SSD in September, it was only a matter of time before the other shoe dropped. The memory giant fabs its own NAND and sells SSDs to PC makers and other corporate customers, but it doesn’t make Micron-branded drives available to everyday consumers. Instead, that market is covered by its Crucial division, which draws from the same pool of in-house technologies. Sooner or later, the M600’s funky SLC/MLC caching scheme was destined pop up in an equivalent Crucial product.

That product is the MX200, which Crucial announced at CES last month. The drive has the same DNA as the M600, and it’s already available for as little as $0.46/GB. But it’s not the whole story.

The MX200 fell into our laps alongside the BX100, an unexpected second shoe more akin to one of those minimalist, barefoot designs that’s basically just a glove for your foot. This trimmed-down alternative uses a completely different controller, and it has an even lower price tag. BX100 SSDs are currently selling for as little as $0.36/GB, making them among the cheapest around.

We’ve been testing the new drives to see how they compare to the current crop of contenders, and the results might surprise you. Turns out there’s something to those funky toe shoes, after all.

Same NAND, different controllers

The MX200 treads familiar territory, so that’s the best place to start. Like its M600 predecessor, the drive combines an eight-channel Marvell 88SS9189 controller with Micron’s own 16-nm NAND.

Each flash die packs 16GB of storage, making it easier to hit higher capacities. The higher-density dies create problems for lower-capacity drives, though. SSD controllers achieve peak performance by addressing multiple dies simultaneously, but smaller drives don’t have enough individual NAND chips to fully exploit that controller-level parallelism. Smaller SSDs typically have slower write performance ratings than their larger counterparts as a result.

To counteract this problem, the MX200 takes advantage of a dynamic switching capability built into Micron’s 16-nm NAND. The flash can switch entire blocks between a single-bit SLC config, whose simpler programming mechanism enables higher write speeds, and a two-bit MLC config, whose greater bit density enables higher capacities. The MX200 writes incoming data to SLC blocks before moving it to MLC zones during idle downtime. The drive essentially treats its entire unused capacity as a dynamic write cache.

Appropriately dubbed Dynamic Write Acceleration, this caching scheme is a clever way to speed up the short, bursty writes typical of client workloads. However, the fact that SLC blocks have half the storage capacity of MLC ones creates problems for sustained transfers. Left unchecked, SLC writes could saturate the drive’s unused flash before its MLC capacity is exhausted. Dynamic Write Acceleration avoids this problem by shifting writes into MLC mode before the flash is completely consumed by SLC blocks. If writes remain relentless, the MX200 eventually starts moving previously cached data into MLC blocks while simultaneously handling incoming writes.

We can see the impact of this three-tiered approach by continuously writing data. This sequential write speed plot from my M600 review nicely illustrates how transfer rates change as the drive fills up:

The higher speeds up to the 46% mark illustrate the performance benefits of writing in SLC mode. The middle portion shows the hit associated with MLC writes, while everything past 58% highlights the severe penalty incurred when the drive is shuffling cached data alongside incoming writes. Yikes.

The 500GB and 1TB versions of the MX200 have a sufficient number of NAND chips for peak performance, so they don’t require Dynamic Write Acceleration. The feature is only enabled on the 250GB drive. It’s also active in the mSATA and M.2 versions of the MX200, both of which are available in 250GB and 500GB capacities. For those drives, write caching is enabled in part to improve power efficiency. Completing writes faster allows the MX200 to return quickly to a low-power state.

Apart from its caching setup, the MX200 mirrors the laundry list of features attached to other recent Crucial SSDs. It has a thermal throttling mechanism that reduces performance when the drive is in danger of overheating, hardware-accelerated AES encryption with support for the requisite IEEE and TCG Opal standards, and an extra layer of RAID-like protection to compensate for physical flash failures. Crucial also throws in a free copy of Acronis True Image HD to ease upgrades from existing systems.

The more budget-minded BX100 has none of that. Under “advanced features,” its spec sheet lists well-worn bullet points like TRIM support and active garbage collection—capabilities pretty much every SSD has had for years. Although the drive can monitor its internal temperature, thermal throttling isn’t part of the package. There’s no support for SLC caching, hardware-based encryption, or RAID-like internal protection. And no mini versions, either. The BX100 is only available in a 2.5″ form factor.

As one might expect, homegrown flash is still part of the equation. The BX100 uses the same 16-nm NAND as the MX200, though the chips are addressed exclusively in MLC mode.

Instead of tapping yet another Marvell controller, the BX100 employs Silicon Motion’s SM2246EN. This four-channel chip has half as many parallel NAND channels, but each one supports transfer rates up to 400MB/s, so internal bandwidth remains plentiful. The most critical bottleneck is the Serial ATA interface, which tops out at less than 600MB/s for the drive as a whole.

As we saw in our review of the Silicon Motion-based Adata Premier SP610, modern four-bangers can mostly keep up with their eight-channel counterparts. Crucial’s performance specifications largely concur. Here are the essential stats for the BX100 and MX200 families. Note that the MX200 starts at 250GB, while the BX100 reaches down to 120GB.

Capacity Max sequential (MB/s) Max 4KB random (IOps) Endurance (TBW) Price $/GB Read Write Read Write BX100 120GB 535 185 87k 43k 72TB $69.99 $0.58 BX100 250GB 535 370 87k 70k 72TB $109.32 $0.44 MX200 250GB 555 500 100k 87k 80TB $139.99 $0.56 BX100 500GB 535 450 90k 70k 72TB $189.99 $0.38 MX200 500GB 555 500 100k 87k 160TB $249.99 $0.50 BX100 1TB 535 450 90k 70k 72TB $374.99 $0.37 MX200 1TB 555 500 100k 87k 320TB $469.99 $0.46

The BX100’s specs largely shadow those of the MX200, though the budget drive’s write speeds are only competitive at higher capacities. The lack of SLC caching really hurts the BX100 120GB and 250GB. Compare those to the MX200 250GB, which enjoys the same performance ratings as its larger siblings. In a moment, we’ll see how the 250GB and 500GB versions of each drive compare in a broad range of tests.

Crucial’s three-year warranty is the same for both drives, but the MX200 has a much higher endurance specification. The 1TB incarnation is rated to withstand 320TB of total writes, a limit that scales down predictably with the total capacity. Meanwhile, the BX100 is rated for 72TB of writes across the board.

Even 72TB is a heck of a lot of writes for a consumer-grade drive. The SSDs in my main desktop are only subjected to a few terabytes of writes per year, and most folks seem to be in the same boat. At that pace, it would take more than a decade just to burn through the BX100. Also, keep in mind that our ongoing SSD Endurance Experiment has demonstrated that SSDs can endure substantially more writes than their official specifications promise.

Curious users can monitor SSD health using Crucial’s new Storage Executive software. This utility displays SMART attributes that log host writes, bad blocks, important errors, and other statistics. The main monitoring pane also shows the MX200’s host writes, but that field is conspicuously absent for the BX100. Weirdly, the required data is still accessible via the SMART attributes.

Storage Executive is a surprisingly bulky 150MB download for something that runs in a web browser. At least the utility has some other functions, including a firmware updater and a secure-erase tool. It doesn’t run automatically when the system is booted, either, making it less obtrusive than some other SSD software.

As usual, we’ve tested Crucial’s new hotness against a staggeringly deep field of SSDs from the past few years. The benchmarking bonanza begins on the next page.

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 may be the last review to use our current suite and test systems. We’ve already started testing drives on new rigs—and with a fresh batch of benchmarks. Stay tuned for those results soon.

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 BX100 and MX200 easier to spot. The M600 is highlighted in a separate shade, providing a reference point for the MX200’s Micron counterpart. Crucial’s older SSDs are also colored to set them apart from the rest of the fray.

The BX100s make an impression right off the bat, posting nearly the fastest sequential read speeds we’ve ever measured. The MX200s aren’t far behind.

CrystalDiskMark’s sequential write speed test turns the tables somewhat. Although the MX200s remain comfortably in the middle of the pack, just behind the fastest contenders, the BX100s tumble down the standings. The 250GB drive is the hardest hit, though it’s still faster than the equivalent MX100, Crucial’s previous budget leader.

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.

Most of the SSDs are evenly matched, with access times ranging from instantaneous to slightly more instantaneous. It’s hard to get excited about differences of only a few microseconds.

The field spreads out a little in the 1MB write test, though. The MX200 250GB turns in the slowest time of the bunch, and the M600 256GB isn’t much faster. Odds are Dynamic Write Acceleration is at fault.

The BX100 250GB isn’t exactly a speed demon with 1MB random writes, either, but it’s way quicker than the equivalent MX200 and slightly ahead of the MX100.

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 BX100 and MX200, so we’re only presenting the used-state scores.

Sorry. I probably should have told you to lube your scroll wheel before whipping through all those graphs.

The MP3, movie, and RAW sets are dominated by larger files, and the MX200 has an edge over the BX100 in those tests. Notice how the MX200 250GB largely keeps pace with its 500GB counterpart, while the smaller BX100 trails its larger twin by wider margins. The MX200 250GB’s Dynamic Write Acceleration seems to pay dividends here.

The smaller files in the Mozilla and TR sets belong to the BX100, however. The 500GB version even takes the top spot overall in the TR test, just a smidgen ahead of an Adata drive based on the same Silicon Motion controller.

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.

The BX100 surprises once again. Both versions have low mean service times for reads and writes. The MX200 500GB also fares well, but the 250GB exhibits clear weakness. It’s not particularly quick with reads, and it’s downright slow with writes.

The M600 256GB is even worse off, possibly because its higher capacity leaves less overprovisioned area for the controller. Dynamic Write Acceleration likely plays a role in the poor performance of both drives. DriveBench 2.0 squeezes an awful lot of writes into a relatively short span, and the caching scheme probably isn’t tuned for such a heavy workload. Also, the idle time provided for garbage collection may be too short to allow the driver to transfer cached data to main storage.

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.

These metrics paint a brighter picture of Dynamic Write acceleration, at least as it’s employed in the MX200 250GB. That drive logs a fraction of the sluggish writes reported by the M600 256GB—and by the BX100. It’s still a few orders of magnitude off the leaders, but it’s a big improvement over Crucial’s older SSDs.

The BX100 250GB suffers more slow writes than we’d like, especially compared to its 500GB twin. Again, though, Crucial has clearly outdone its previous offerings. The older MX100 has more service times over 100 milliseconds with both reads and writes.

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 BX100 and MX200 to 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.





The BX100 250GB and 500GB are evenly matched in IOMeter. The MX200 250GB delivers slightly more IOps than those drives across our escalating load, while the 500GB leaves them in the dust. Even the BX100s compare favorably to Crucial’s older SSDs, especially the MX100 256GB.

Versus the rest of the field, the BX100s are middle-of-the-pack performers. That’s pretty good considering their pricing. With few exceptions, the only drives that score higher cost substantially more.

Even without a bargain-basement sticker on its side, the MX200 500GB still looks strong. It has among the highest I/O rates at the low queue depths typical of desktop workloads. The 250GB version turns in a respectable overall performance, too, but it’s clearly a step behind.

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 SATA SSDs we’ve tested over the past few years have been within about a second of each other in these tests. I’m hopeful our new load-time tests—and PCIe SSDs—can tease out more meaningful differences. Stay tuned.

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.

Crucial’s new drives are relatively power-efficient. They consume less juice at idle than the company’s older models, and the BX100s are especially frugal under load. That drive’s four-channel controller probably consumes less power than the eight-channel chip in the MX200.

So ends our performance analysis. 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 BX100 250GB Silicon Motion SM2246EN 16-nm Micron sync MLC Crucial BX100 500GB Silicon Motion SM2246EN 16-nm Micron sync 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 Crucial MX200 250GB Marvell 88SS9189 16-nm Micron sync SLC/MLC Crucial MX200 500GB Marvell 88SS9189 16-nm Micron sync SLC/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 Micron M600 256GB Marvell 88SS9189 16-nm Micron sync SLC/MLC Micron M600 1TB Marvell 88SS9189 16-nm Micron sync SLC/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 EVO 250GB Samsung MGX 32-layer Samsung V-NAND TLC Samsung 850 EVO 1TB Samsung MEX 32-layer Samsung V-NAND TLC Samsung 850 Pro 512GB Samsung MEX 32-layer Samsung V-NAND MLC 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.

If you’ve made it this far, you might enjoy a couple more shots of the BX100 and MX200.

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 Crucial BX100 250GB with MU01 firmware Crucial BX100 500GB with MU01 firmware Crucial MX200 250GB with MU01 firmware Crucial MX200 500GB 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 Micron M600 256GB with E100 firmware Micron M600 1TB with E100 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 EVO 250GB with EMT01B6Q firmware Samsung 850 EVO 1TB with EMT01B6Q 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.