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Today's solid-state drives: The value perspective


Quantifying the value of today's SSD goodness
— 5:16 PM on July 6, 2010

Value comparisons have become a bit of a tradition here at TR. We rolled out our first CPU value article way back in 2007 and followed up with a second look a year later. A quantitative assessment of the value proposition has since become an integral part of our CPU reviews, and we've even considered the value of graphics cards. What can I say? We loves us some scatter plots.

So should enthusiasts. A quest for the best value is deeply ingrained within the community's collective psyche. We're interested in getting the best bang for our buck—finding the proverbial sweet spot that delivers the fastest possible performance at a reasonable or at least justifiable cost. Our value scatter plots tackle performance and price at the same time, neatly mapping a landscape that we can then scour for the best combination of those elements.

If you've been keeping up with TR over the last few months, you'll know that I've been hunkered down in the Benchmarking Sweatshop testing a torrent of solid-state drives on our brand-new pair of storage test rigs. The Twins have churned through a dozen SSD configurations in the last little while, neatly bringing us up to date with the latest drives, controllers, and firmware from all the usual suspects.

The SSD market doesn't stagnate, so we're going to make use of this data set while it's still fresh, bringing our value perspective into the storage realm for the very first time. Join us as we pore over pages of scatter plots to determine which solid-state drives have the most convincing value proposition.

The contenders
Before getting our hands dirty, let's familiarize ourselves with the collection of SSDs that we'll be considering today. The chart below neatly summarizes the key specifications of all of the contenders we've assembled. Since retail and e-tail pricing tends to change with great frequency, we've tried to simplify things some by relying on Newegg for all of our pricing data. That should give us a good idea of the price differences between the drives. For the Force F100, which is no longer being stocked and may be discontinued, we've gone with the drive's last selling price.

Flash controller Cache size Total capacity Price
Corsair Force F100 SandForce SF-1200 NA 100GB $410
Corsair Force F120 SandForce SF-1200 NA 120GB $349
Corsair Nova V128 Indilinx Barefoot ECO 64MB 128GB $349
Crucial RealSSD C300 Marvell 88SS9174 256MB 256GB $660
Intel X25-M G2 Intel PC29AS21BA0 32MB 160GB $405
Intel X25-V Intel PC29AS21BA0 32MB 40GB $110
Kingston SSDNow V+ Toshiba T6UG1XBG 128MB 128GB $319
OCZ Agility 2 SandForce SF-1200 NA 100GB $310
OCZ Vertex 2 SandForce SF-1200 NA 100GB $325
Plextor PX-128M1S Marvell 88SS8014 128MB 128GB $389
WD SiliconEdge Blue JMicron JMF612 64MB 256GB $668

The newest kids on the block are based on SandForce's SF-1200 controller, which impressively makes do without an onboard DRAM cache. We have examples from both OCZ and Corsair covering the 100GB and 120GB capacity points. All four have 128GB of NAND flash onboard, but firmware with a lower overprovisioning percentage allows the F120 to offer 120GB of user capacity, while the others only serve up 100GB of usable storage. We've found the F120 to be slower than the F100, likely because of the difference in overprovisioning.

Indilinx's Barefoot ECO controller is a slightly revised version of the original Barefoot design popularized by early enthusiast-targeted SSDs like the first-generation OCZ Vertex. Corsair's Nova is a typical example of what has become quite a common and popular breed.

We've only seen Marvell's 88SS8014 controller in Plextor's PX-128M1S, and that's probably a good thing. This older controller lacks TRIM support and is thus rather undesirable for anyone running Windows 7 or recent versions of Linux that support the command. Fortunately, the Marvell 88SS98174 in Crucial's RealSSD C300 implements TRIM. The C300 also has a massive 256MB cache and support for 6Gbps SATA connectivity. For the sake of apples-to-apples comparisons, we're using test results with the C300 running on the same 3Gbps SATA controller as all the other SSDs.

JMicron got a bad rap in the early days of consumer SSDs, but the SiliconEdge Blue's JMF612 storage controller is much more competent than the company's first efforts. Western Digital co-developed the Blue's firmware with JMicron, and the enhancements it made aren't being shared with other drive makers. As a result, the SiliconEdge may perform differently than other SSDs based on the JMF612. We've yet to see another SSD using the Toshiba controller inside Kingston's SSDNow V+. Be careful confusing that drive with other members of the V series, which lack the + and use different controllers.

Finally, we have Intel's entries in our value sweepstakes. The X25-M and X25-V are both powered by a second-gen controller that crucially adds TRIM support. Interestingly, the Intel drives have much less cache memory than the others. Well, with the exception of the cache-less SandForce SSDs, anyway. The X25-V is also by far the cheapest of the bunch, albeit with only 40GB of total capacity.

Although we don't have an SSD from each and every drive maker, all of the contemporary controllers are represented. That's important because a solid-state drive's controller and associated flash memory largely determine its overall performance, much like a graphics card's GPU and memory dictate its frame rates more than the sticker on the cooler.

We can only speak to the performance data we've collected ourselves, so we haven't generalized the results to encompass every manufacturers' implementation of each controller. Do keep in mind, though, that SSDs based on the same controller architecture should offer largely equivalent performance, regardless of which company's name appears on the outside of the drive.

I should also note that storage capacity can play a role in SSD performance. Drives with fewer gigabytes on offer don't always have enough flash memory chips to take advantage of all the parallelism available in multi-channel controllers. Lower-capacity flash chips can also be slower than higher-density ones that pack more dies per package. Again, we can only speak to the results that we've gathered; trying to extrapolate the performance of lower-capacity models based on differences in manufacturer specifications would be dodgy at best. However, we have attempted to compensate somewhat by considering value not only in terms of a drive's absolute price, but also its associated cost per gigabyte. Lower rungs on the capacity ladder tend to have a comparable cost per gigabyte to their higher-capacity counterparts.

Spindle speed Cache size Platter capacity Total capacity Price
Seagate Momentus 7200.4 7,200 RPM 16MB 250GB 500GB $75
Seagate Momentus XT 7,200 RPM 32MB 250GB 500GB $130
WD Caviar Black 2TB 7,200 RPM 64MB 500GB 2TB $190
WD Scorpio Black 7,200 RPM 16MB 160GB 320GB $60
WD Scorpio Blue 5,400 RPM 8MB 375GB 750GB $115
WD VelociRaptor VR150M 10,000 RPM 16MB 150GB 300GB $190
WD VelociRaptor VR200M 10,000 RPM 32MB 200GB 600GB $280

Speaking of cost per gigabyte, it's no secret that SSDs offer rather poor value on the capacity front compared with mechanical hard drives. We have test results for a collection of traditional hard drives, including Western Digital's flagship 7,200-RPM Caviar Black 2TB, the latest 10K-RPM VelociRaptor, and a handful of notebook drives that share the same 2.5" form factor as our SSDs. All of those drives will appear in our value analysis to provide some additional context. Seagate's mechanical/flash Momentus XT hybrid is coming along for the ride, as well.