SATA 6Gb/s? That‘s so 2011. This solid-state drive uses PCI-E (directly) to add storage to a desktop.
There's been a big impact in the high-end solid-state drive market with the release of Sandforce's SF-2281 high-speed SSD controller. This controller has seen the launch of a number of drives capable of easily reaching the 500MB/s transfer mark, and the prices of less speedy drives have come down somewhat. What is a huge surprise is that a few mere months since these high-speed SSDs hit the market, we'd be talking about a product that can blow them out of the water.
The RevoDrive 3 X2 PCI-Express SSD is not a new concept. This solid-state drive uses PCI-E (directly) to add storage to a desktop, bypassing the more typical SATA 2 and SATA 6Gb/s ports the vast majority of desktop systems use. It sounds like a simple system, plug in a card and you get a huge whopping whack of super-fast storage, but it's not always that simple.
Older versions of this technology had limitations on how you could set them up; you might not have been able to boot off them, and options like TRIM weren't necessarily implemented. The RevoDrive 3 X2 solves those problems, and offers big capacities of 480GB and 960GB with boot functionality.
These devices are built like a miniature storage subsystem on a card. The card includes a PCI-E to SAS interface like one you'd normally find in a chipset, or from vendors like Marvell or Adaptec integrated into a motherboard. The card is governed by an OCZ branded SuperScale controller. Attached to this are large amounts of high-speed SSD storage split over a number of storage controllers. In the case of the RevoDrive 3 X2 models, that's four high-speed SandForce SF-2281 chips, each with its own bank of NAND storage attached.
OCZ's further invested in developing what it calls Virtualized Controller Architecture 2.0 (VCA2). This architecture unloads the ordering and data allocation from the CPU onto the card, taking care of the balancing between the multiple SandForce controllers and its subsequent NAND storage. VCA2 acts as an intermediary layer between the OS and hardware and the actual storage, allowing the PC to treat it as if these separate controllers are just one big drive. Because of the VCA2 design, it theoretically lets OCZ use TRIM (or more correctly SCSI UNMAP – the SAS version of TRIM) on the storage. It's theoretical because Windows 7 doesn't support SCSI UNMAP or TRIM via RAID controllers – and we don't have any idea when that support might be added.
Like most SSDs, there's very minimal seek/access times, and far superior throughputs to mechanical hard-disk drives. Now, this is where it gets most interesting. This drive, the OCZ RevoDrive 3 X2, runs at three times the speed of the fastest SSD we've ever benchmarked. Because it's not limited by the SATA port throughput (in the case of SATA 2 at least) and is essentially arranged as a RAID on a card, the OCZ RevoDrive 3 X2 we clocked at roughly 1.5GB/s (yes, that's gigabytes, not bits) per second throughput for read and write.
The drive is optimised for read speeds, and to be precise we benchmarked this card using artificial benchmark ATTO Disk Benchmark at 1,567MB/s. That's in comparison to the Patriot Wildfire we reviewed recently at 556MB/s read speeds. Real benchmarks, including copies and move operations were unfortunately limited by the other disks we were trying to move from, but internal copy operations using batches of smaller files were typically finished at speeds of 1.2GB/s (there's overhead to do with smaller files, and the way SSDs need to allocate them evenly to its storage space).
Unlike off-the-shelf SSD drives using SATA connectors, there are some things you need to keep in mind when plonking one of these in your system. The device needs the bandwidth of a PCI-E x4 slot, and they‘re not all created equal. Different motherboards may have x4 physical slots, but not offer x4 electrical connections to it, or the slots might be deactivated if you run SLI, or other high-bandwidth devices; after all, there are only so many to go around. Our test bench saw the drive not being able to go over around 500MB/s until we switched it to slot 0 – the first full-length slot typically used for your VGA card. But it did take some stuffing around to get it working to its potential. There‘s a great technical forum run by OCZ to get help, and a list of motherboards known to work properly with the RevoDrive X2 you should check before stumping up the cash to avoid disappointment. Once it was running at full speed, we had no other issues in getting it going, Windows installed and the system ticking along.
There's a term used heavily by IT pundits when they‘re talking about something that‘s radically different to existing IT solutions, or orders of magnitude more effective, faster or cheaper. The term is "a disruptive technology" because it disrupts the status quo. Whether you think this is a disruptive technology is your own decision to make.
Though SandForce SF-2281 equipped 550+MB/s drives aren't capable of saturating the 700MB/s maximum throughput of SATA 6Gb/s ports (yet), considering the short period of time that SATA 6Gb/s has been available, we're quickly approaching its maximum potential.
So does this drive and others like it ring in the death knell of SATA-based storage devices? Shortly upcoming processors like the Sandy Bridge-E Intel Core i7-3000 series are loaded with PCI-E lanes that are perfectly suited for these kinds of storage devices. The rest remains to be seen.
Available from OCZ, retailing for $1,949.
APC rating: 8/10 (Highly Recommended)