OCZ Revodrive 120GB

Mass-storage has long been a bottleneck for computer performance and we’re only now starting to see serious improvements in this area, through solid-state drives (SSDs).

The performance boost SSDs bring is considerable – enough to make even the current 300Mbytes/s that SATA 2.0 is capable of seem inadequate. SATA 3.0 will take that to 600MBytes/s but with newer flash memory controllers in SSDs, a few of those disks in RAID-0 configuration could easily saturate even the newer storage bus.

Memory specialist OCZ has a solution to this, and it’s simple: use PCI-Express. The company’s RevoDrive range of drives uses four lanes of PCI Express, which gives the devices a theoretical 2 GBytes/s of bandwidth to play with, far more than the fastest SATA interface.

The card we reviewed was the 120GB model, and OCZ’s engineering is fascinating. Essentially, the card comprises two 60GB drives that are RAIDed together; RAID-0, 1, 5 and 10 are possible through an onboard Silicon Image Si3124 SATA-300 controller.

SATA is still with us on the RevoDrive, in other words, ditto PCI-X; an interface standard that gave way to PCI-Express. OCZ takes all these different interfaces and technologies, integrates them onto the RevoDrive and bridges the lot to PCI-Express.

This is quite a complex solution, but it does mean OCZ has been able to produce a PCI-Express SSD that costs $599 instead of many thousands of dollars – and it boots Windows too.

The MLC flash memory on the SSDs is driven by high-performance SandForce SF-1200 controllers; SandForce specifies these as able to provide 260MBytes/s sequential reads and writes with 128KByte blocks, which is very good.

All the combined technology works rather well together in real life. Installing the RevoDrive is easy, and most newer systems should work with it. You need to set up the drives in the Silicon Image BIOS utility (I picked RAID-0 with 128Kbyte stripe for best performance and space) and grab a driver for Windows (Mac OS X is not supported).

Windows 7x64 installed without a hitch on the RevoDrive, which was seated in a Dell T3500 system with a six-core 2.93GHz Intel Xeon processor for testing. Due to the SandForce controller using some of the flash memory blocks as spares, you get 111GB of the nominal 120GB space in RAID-0.

Seeing the Windows Experience Index for disk performance jump from 6.2, courtesy of dual 300GB 10,000 rpm Western Digital VelociRaptors, to the maximum 7.9 with the RevoDrive installed gave a foretaste of just how quick the OCZ drive is.

OCZ rates the drive at maximum speeds of 540MBytes/s reads, 480MBytes/s writes and 40,000 I/Os per second; staggeringly high figures. The benchmarks show that under certain conditions such as sequential access to non-random data in appropriate block sizes, you can hit those numbers.

Using more real-world oriented testing, such as with Intel’s IO Meter and workstation load profile that features 8KByte transfer sizes, 32 outstanding I/O requests and all CPU cores working, the figures weren’t quite as sky high but very good nevertheless.

Without putting too fine a point on it, the RevoDrive blew the VelociRaptors out of the water; in most tests by a huge margin.

As a convenient, high-performance multi-drive SSD solution for enthusiasts and specialist users, OCZ’s RevoDrive is unique in its price range.

That said, the pricing needs to come down by a good chunk for the RevoDrive to be competitive against standard SSDs. Take two 60GB OCZ Vertex 2 E Series drives for instance, and you’ll save $150 over the RevoDrive. With individual drives, you can also add to the storage arrays, and remove disks too.

The RevoDrive is a great product that delivers on its performance claims, and we’re looking forward to OCZ further developing the concept – and lowering the price. Just a little bit cheaper, and the RevoDrive would be a killer product.