The rest of the RevoDrive
The third-generation RevoDrive is available in a bunch of different flavors. Today, we're looking at the RevoDrive 3 X2, whose suffix refers to the double-decker circuit board used to accommodate the four SandForce controllers and their associated NAND. The vanilla RevoDrive 3 uses a single circuit board but still features dual SandForce controllers. To avoid confusion, it would probably be better to call the single- and dual-board models the RevoDrive 3 X2 and X4, respectively. In my view, counting controllers makes more sense than counting circuit boards.
In addition to two board configurations, the RevoDrive 3 is available with a couple of different kinds of memory. The Max IOps versions are equipped with Toshiba's 32-nm Toggle DDR NAND, the same memory used in the Vertex 3 Max IOps edition. The standard variants employ ONFI-compatible flash built on Micron's 25-nm process. This asynchronous flash is similar to what's found in OCZ's Agility 3 SSD and other mid-range SandForce SSDs.
Somewhat surprisingly, OCZ doesn't offer a version of the RevoDrive 3 based on synchronous NAND. That particular breed of flash is commonly found in high-end SandForce SSDs like OCZ's vanilla Vertex 3, which is positioned just below the Max IOps model. There probably isn't enough of a market for the RevoDrive 3 to justify a third memory tier.
Unfortunately, asynchronous NAND is definitely slower than the synchronous stuff. Micron's datasheet for the RevoDrive's 29F64G08CBAAA flash packages lists a per-pin transfer rate ceiling of 50 MT/s. The synchronous version of this NAND (part number 29F64G08CBAAB, for those following along with their decoder rings home) is rated for speeds up to 200 MT/s. Both versions will endure at least 3,000 write-erase cycles, according to Micron.
|Dies per package||Max sequential (MB/s)||Max 4KB random writes (IOps)||Price|
|240GB||32 x 64Gb||1||1500||1225||200,000||$680|
|480GB||64 x 64Gb||1||1500||1250||230,000||$1,600|
|960GB||128 x 64Gb||2||1500||1300||230,000||$3,150|
Our RevoDrive 3 X2 240GB is the least expensive of the async X2 cards, and its specifications are detailed in the table above. OCZ adds NAND dies to hit the higher capacities, and the price climbs accordingly. The performance ratings also rise with capacity, but only slightly. The difference in sequential writes between the fastest and slowest models amounts to only 6%, and the gap in random writes is still fairly modest at 14%. All three members of the family have the same sequential read speed rating.
Take a moment to let those projected performance numbers really sink in. We're talking about transfer rates in excess of 1GB/s. The X2s are purportedly capable of pushing hundreds of thousands of 4KB random writes, although OCZ oddly doesn't quote a figure for random reads.
The single-board RevoDrive 3 is available in 120, 240, and 480GB capacities—exactly half the storage at each step up the X2 ladder. With fewer controllers at their disposal, these models have lower performance ratings than X2 drives with the same capacities. The Max IOps variants of the single-board and X2 configs predictably boast higher performance specifications than their asynchronous counterparts. In the X2, switching to Toggle DDR NAND purportedly boosts sequential throughput as high as 1600MB/s, while random writes climb to 240,000 IOps.
Regardless of whether they have a second layer, all the RevoDrive 3 cards are single-slot designs. The base circuit board measures 6.6" (168 mm) long, so it should be easy to squeeze into smaller systems.
The drive's power consumption looks relatively modest given the hardware involved. OCZ's says the X2 consumes 13.5W at idle and 14.3W when active, which seems like a lot for a 240GB SSD. But remember that this is more like four 60GB SSDs with an additional controller tacked on.
Somewhat surprisingly given the RevoDrive's workstation aspirations, OCZ's warranty runs out after three years. We're used to premium storage solutions offering five-year warranty coverage, making the shorter term a notable blemish on the Revo's record.
To its credit, OCZ has improved the Toolbox application used to manage its SSDs. The interface is much prettier than early incarnations, and the app does a fine job of downloading and applying firmware updates. It can also secure-erase the RevoDrive if the SSD is connected as secondary storage (rather than as a boot drive). Wiping the Revo is much easier than secure-erasing an SSD RAID array, which must first be broken before member drives are wiped individually. That'll be loads of fun with a comparable four-drive array. OCZ would do well to make the message indicating a successful secure erase more prominent, though; right now, it's buried in the lower-left corner and barely visible.
We'd also like to see a revamped interface for monitoring SSD-specific SMART attributes. In addition to logging the total volume of host reads and writes, the RevoDrive can tell you how much life it has left and what percentage of its NAND blocks have been retired from service. These attributes pop up in a simple text window and would be better presented within the main interface.