Our testing methods
If you're unfamiliar with The Twins, our new duo of storage test platforms, I recommend checking out this page from our recent VelociRaptor VR200M review. These systems pack potent hardware and have been furiously testing hard drives and SSDs for months now. Unfortunately, Intel still hasn't resolved the performance scaling issue we found in its latest storage controller drivers for the P55 chipset. As a result, The Twins are still running the Microsoft AHCI driver built into Windows 7.
Before dipping into pages of benchmark graphs, let's set the stage with a quick look at the players we've assembled for comparison. We've called up a wide range of competitors, including a selection of desktop hard drives, traditional notebook drives, Seagate's Momentus XT hybrid, and a cubic assload of pure solid-state goodness. Below is a chart highlighting some of the key attributes of the contenders we've lined up.
|Flash controller||Interface speed||Spindle speed||Cache size||Platter capacity||Total capacity|
|Agility 2|| SandForce
|Caviar Black 2TB||NA||3Gbps||7,200 RPM||64MB||500GB||2TB|
|Force F100|| SandForce
|Momentus 7200.4||NA||3Gbps||7,200 RPM||16MB||250GB||500GB|
|Momentus XT||NA||3Gbps||7,200 RPM||32MB||250GB||500GB|
|RealSSD C300||Marvell 88SS9174||6Gbps||NA||256MB||NA||256GB|
|Scorpio Black||NA||3Gbps||7,200 RPM||16MB||160GB||320GB|
|Scorpio Blue||NA||3Gbps||5,400 RPM||8MB||375GB||750GB|
|SiliconEdge Blue||JMicron JMF612||3Gbps||NA||64MB||NA||256GB|
|SSDNow V+||Toshiba T6UG1XBG||3Gbps||NA||128MB||NA||128GB|
|VelociRaptor VR150M||NA||3Gbps||10,000 RPM||16MB||150GB||300GB|
|VelociRaptor VR200M||NA||6Gbps||10,000 RPM||32MB||200GB||600GB|
|Vertex 2|| SandForce
|X25-M G2||Intel PC29AS21BA0||3Gbps||NA||32MB||NA||160GB|
On the SSD front, we've collected all the relevant players, including drives based on Indilinx, Intel, JMicron, Marvell, SandForce, and Toshiba controllers. Although it might not seem like a fair fight, we've also thrown in results for a striped RAID 0 array built using a pair of Intel's X25-V SSDs. The X25-V only runs a little more than $100 online, making multi-drive RAID arrays affordable enough to be tempting for desktop users. Our X25-V array was configured using Intel's P55 storage controller, the default 128KB stripe size, and the company's latest 126.96.36.1994 Rapid Storage Technology drivers.
Although our test system's P55 chipset is limited to 3Gbps Serial ATA, the motherboard has an auxiliary Marvell 9128 storage controller with two 6Gbps SATA ports. In addition to testing the RealSSD connected to the P55's storage controller, we've benched the drive with it attached to the Marvell chip running the latest 188.8.131.526 drivers.
I should note that we've actually had a C300 in our possession for several months now. The drive's initial firmware release exhibited serious performance issues, so we elected to wait for an update that Crucial promised would address the problem. That update came in the form of a 0002 firmware release made available on Crucial's website last month. We've used this latest 0002 firmware for all our testing.
The block-rewrite penalty inherent to SSDs and the TRIM command designed to offset it both complicate our testing somewhat, so I should explain our SSD testing methods in greater detail. Before testing the drives, each was returned to a factory-fresh state with a secure erase, which empties all the flash pages on a drive. Next, we fired up HD Tune and ran full-disk read and write speed tests. The TRIM command requires that drives have a file system in place, but since HD Tune requires an unpartitioned drive, TRIM won't be a factor in those tests.
After HD Tune, we partitioned the drives and kicked off our usual IOMeter scripts, which are now aligned to 4KB sectors. When running on a partitioned drive, IOMeter first fills it with a single file, firmly putting SSDs into a used state in which all of their flash pages have been occupied. We deleted that file before moving onto our file copy tests, after which we restored an image to each drive for some application testing. Incidentally, creating and deleting IOMeter's full-disk file and the associated partition didn't affect HD Tune transfer rates or access times.
Our methods should ensure that each SSD is tested on an even, used-state playing field. However, differences in how eagerly an SSD elects to erase trimmed flash pages could affect performance in our tests and in the real world. Testing drives in a used state may put the TRIM-less Plextor SSD at a disadvantage, but I'm not inclined to indulge the drive just because it's using a dated controller chip.
With few exceptions, all tests were run at least three times, and we reported the median of the scores produced. We used the following system configuration for testing:
We used the following versions of our test applications:
- WorldBench 6
- Intel IOMeter 2006.07.27
- Xbit Labs File Copy Test 0.3
- HD Tune 4.01
- Visual Studio 2008 with 03-23-2010 Firefox source
- Call of Duty: Modern Warfare 2
- Crysis Warhead
The test systems' Windows desktop was set at 1280x1024 in 32-bit color at a 75Hz screen refresh rate. Vertical refresh sync (vsync) was disabled for all tests.
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.