|Introduction and Specifications|
|If you've been reading the pages of HotHardware for any length of time, you've probably noticed that we have an affinity for just about anything SSD related. As performance enthusiasts at heart, it's no wonder why we're keenly focused on the market segment, but even so, there are standout products that tend to pique our interest more than others. And in the burgeoning SSD market, there's nothing more interesting than PCI Express based SSDs.
In recent months we've covered PCI Express-based SSDs from virtually all the major players, from Fusion-io to, OCZ and LSI. The last time we took a look at OCZ's offering, the RevoDrive X2 took to the test bench and with its MLC-based design, offered much of the performance of significantly more expensive SLC-based PCI Express SSDs, but at a fraction of the cost. Today the third coming of the RevoDrive from OCZ is upon us, with all new technology on board, from its Flash controllers to the RAID processor. With read/write specs that will make you drool, the RevoDrive 3 X2 is here and if it lives up to its specifications on paper, we think you're going to want to stick around for the intimate details on the pages that follow.
RevoDrive 3 240G @ $699.99OCZ's RevoDrive series is their "prosumer" targeted product-line, based on MLC NAND Flash, and with price points that are much more in line with traditional high-end SATA-based solid state drives. At $699 for the 240GB variant, the RevoDrive 3 X2 drops in at under $3 per GB of storage.
Update, 6/28 6:05PM - Bear in mind that the 240GB variant of the RevoDrive 3 is not actually an "X2" model but rather a single PCB with two SandForce controllers on board, versus four on the X2 version. This will leave you with theoretically half of the available read/write bandwidth.
The higher densities are a bit more expensive, with the 480GB and 960GB versions weighing in at $3.53 and $3.33 per GB, respectively. On average, that's about a $1 per GB premium over the average SATA III (6Gbps) SSD. However, with max read throughput of 1.5GB/sec and max writes at 1.2GB/sec, OCZ is claiming to offer a theoretical 3X performance boost over the fastest standard SATA products on the market right now.
|The RevoDrive 3 X2 and VCA 2.0|
|The RevoDrive 3 X2 employs an entirely new processor and controller architecture. The first generation of RevoDrive products made use of Sandforce SF-1200 series Flash controllers and now the RevoDrive 3 is taking advantage of SandForce's latest SF-2200 series controller, with four SF-2281 chips per RevoDrive 3 X2 design, two on each of the card's dual PCBs. These SandForce controllers are 6Gbps SATA capable with a max sequential read/write speed of 500MB/s respectively and a max throughput of 60K IOPS with 4K transactions. These are the same SSD controllers you can find on OCZ's Vertex 3 series drives, along with Micron NAND Flash.
These four controllers, two on the daughter card, all connect serially to a main RAID processor on the base board and that's pretty much where the real magic happens. Figuratively at least, because OCZ is holding details of the main RAID processor technology very close to the vest.
Where we scoffed a bit at the previous generation RevoDrive's implementation of a PCI-X to PCIe bridge, bolted up to a Silicon Image PCI-X RAID controller, the RevoDrive 3's design is dramatically more elegant, with fewer chips to get the job done and native PCI Express links on the back-end to talk over the edge connector of the card.
The "magic" we spoke of earlier happens in OCZ's ICT-0183 chip that you can clearly see in the shot above (right). This is what OCZ is calling their "SuperScale Storage Accelerator." If you follow the traces to and from the chip, you'll note very neat and clean serial pairs from the SandForce controllers (SATA links) and on the back side of the chip there are four more pairs running down to the edge connector; these are PCI Express links -- a X4 Gen 2 connection to be specific. Easy right? Not so fast. There's a lot that's going on under the hood of OCZ's ICT-0183 SuperScale processor. Though OCZ would not confirm this, we believe the ICT-0183 is actually based on Indilinx intellectual property and technology that OCZ picked up when they acquired the company back in March of this year. OCZ now also has a large team of 80+ software engineers at their disposal with the Indilinx acquisition.
We're told OCZ's new SuperScale storage processor is a combination of ARM cores, SATA and PCI Express interfaces and of course a bit of bridging in between them. OCZ didn't give us specifics of the processing engines within the SuperScale Accelerator, but they did give us a high-level functional block diagram that shows what's going on with the RevoDrive 3 X2's design implementation.
OCZ's SuperScale Storage Accelerator (left) with VCA 2.0 - System Topology
So what we're looking at here is OCZ's Virtualized Controller Architecture (VCA), as it is implemented in the RevoDrive 3 X2. OCZ's SuperScale processor is the square block on the left, where command queuing and load balancing takes place. As it turns out, the SuperScale Accelerator is much more than just a simple RAID controller and SATA to PCIe bridge. It also supports what OCZ is a calling "Complex Command Queuing Structure" or CCQS. CCQS is a combination of Tagged Command Queuing (TCQ) and Native Command Queuing (NCQ) and along with what OCZ calls their "QBA" or Queue Balancing Algorithm, performance is optimized and workloads are balanced across the drive's RAID stripe with all controllers on the board. OCZ can also bring out up to two SuperScale processors per PCI Express slot/card. However, RAIDing a pair of RevoDrive 3 X2s cards together, though possible, is not recommended. OCZ notes that their upcoming Z-Drive R4, the enterprise class version of the RevoDrive so to speak, will officially support this.
Finally, as we mentioned, OCZ is talking up their VCA technology again with the RevoDrive 3 X2 and they're claiming that this is the second generation of their Virtualized Controller Architecture, that was briefly and quietly introduced a few months back with the Z-Drive R3. Yes, we missed the first iteration too but hey, who's counting, and we'll assume 2.0 is better than the first gen. The Z-Drive R3 didn't make it to market in any great quantity, so it will be interesting to see how VCA 2.0 takes off with the RevoDrive 3 X2 and the upcoming Z-Drive R4.
Regardless, OCZ's also claims the SuperScale Processor on board the RevoDrive 3 X2, supports the VCA 2.0 architecture and offers the following benefits natively.
|Test System SANDRA Physical Disk Tests|
Our Test Methodologies: Under each test condition, the SSDs tested here were installed as secondary volumes in our testbed, with a standard spinning hard disk for the OS and benchmark software installations. The SSDs were left blank without partitions wherever possible, unless a test required them to be partitioned and formatted, as was the case with our ATTO, Vantage, and CrystalDiskMark benchmark tests, as well as one of the IOMeter runs. Windows firewall, automatic updates and screen savers were all disabled before testing. In all test runs, we rebooted the system and waited several minutes for drive activity to settle before invoking a test.
For our first set of tests, we used SiSoft SANDRA, the the System ANalyzer, Diagnostic and Reporting Assistant. Here, we used the Physical Disk test suite and provided the results from our comparison SSDs. The benchmarks were run without formatting and read and write performance metrics are detailed below.
SANDRA's purely sequential and rather short read/write tests show the RevoDrive 3 X2 is easily the fastest of the group, even faster than Fusion-io's very expensive ioDrive, which is an SLC-based card in the $7K range. This test shows the RevoDrive 3 X2 is offering up a solid 1GB/sec read/write performance, which is slightly less than OCZ's maximum rating for the drive. However, again, SANDRA's Physical Disk test isn't exactly a comprehensive view of performance, but rather a quick and dirty look at burst bandwidth. Let's dig deeper.
|IOMeter Test Results|
As we've noted in our previous SSD coverage, though IOMeter is clearly a well-respected industry standard drive benchmark, we're not completely comfortable with it for testing SSDs. The fact of the matter is, though our actual results with IOMeter appear to scale properly, it is debatable whether or not certain access patterns, as they are presented to and measured on an SSD, actually provide a valid example of real-world performance for the average end user. That said, we do think IOMeter is a gauge for relative available bandwidth with a given storage solution. In addition there are certain higher-end workloads you can invoke on a drive with IOMeter, that you really can't with any other benchmark tool available currently.
In the following tables, we're showing two sets of access patterns; our Workstation pattern, with an 8K transfer size, 80% reads (20% writes) and 80% random (20% sequential) access and our Database access pattern of 4K transfers, 67% reads (34% writes) and 100% random access.
The first thing you'll note here is how flat the standard SATA SSD's performance was across test patterns and IO queue depth. The IO queue depth set in IOMeter essentially represents higher levels of workload requests of the same access patterns simultaneously. The Vertex LE SSD was saturated here as we turned up queue depth. However, the entire group of PCI Express-based SSDs scaled up significantly at higher request levels. OCZ's RevoDrive line-up flattens out at a queue of 144 or so in this test, with the RevoDrive 3 X2 putting out significantly higher IO response versus the previous generation RevoDrive and Fusion-io ioXtreme drives, but not quite catching the significantly more expensive ioDrive and LSI WarpDrive.
Our database access pattern showed much of the same performance grouping as we saw in the Workstation setup. However, with a higher write workload and smaller 4K transfers, the RevoDrive 3 X2 is further distanced from it's über-expensive SLC competitors. And that's really where the rubber meets the road here. SLC SSDs inherently have higher available write bandwidth, on average, over MLC based products, all other things being equal. However, architectural, with OCZ's SuperScale Acclerator and SandForce SF-2200 series controllers, all other things are not equal and we have one final IOMeter run we'd like to show you that demonstrates this a bit.
The workload you see represented in this graph has become a bit "industry standard" as of late, though we'd offer that it still should be taken with a grain of salt. Again, what we're looking at here is one set access pattern that is concurrently sprayed across the drive volume by IOMeter until the drive reaches its saturation point. In this IOMeter run, we should note that drives were formatted and blank and were allowed to sit idle for several hours before invoking a test, so that each drive's maintenance algorithms had a chance to maximize performance. The results here show that the RevoDrive 3 X2 is actually able to surpass Fusion-io's ioDrive by a wide margin of about 55%. Conversely, the LSI WarpDrive offers a bit more throughput beyond the RevoDrive 3 X2 as well as the FIO card.
|ATTO Disk Benchmark|
|ATTO is another quick-take type of synthetic disk benchmark that measures transfer speeds across a specific volume length. It measures raw transfer rates for both reads and writes and graphs them out in an easily interpreted chart. We chose .5kb through 8192kb transfer sizes and a queue depth of 10 over a total max volume length of 256MB. ATTO's workloads are sequential in nature and measure raw bandwidth, rather than IO response time, access latency etc. This test was performed on blank, formatted drives with default NTFS partitions in Windows 7 x64.
In ATTO testing, the RevoDrive 3 X2 drive showed some of the highest overall read and write bandwidth of the seven SSD solutions we compared here and in some cases by a wide margin. Also, it's impressive to see just how linear and clean the RevoDrive 3 X2's performance was, starting at 16K transfer sizes, all the way up to 8MB. In 8K or less transfer sizes, only the Fusion-io cards were able to outpace the RevoDrive 3 X2, though again, the price premium for the Fusion-io product definitely sets it apart from OCZ's consumer-like price points.
CrystalDiskMark is a synthetic benchmark that tests both sequential as well as random small and large file transfers. It does a nice job of providing a quick look at best and worst case scenarios with regard to SSD performance, best case being larger sequential transfers and worse case being small, random transfers.
The RevoDrive 3 X2 shows dramatically faster write performance versus the previous generation RevoDrive product and in sequential transfers, almost gets within sneezing distance of the ioDrive. In small 4K writes it's actually able to hang with Fusion-io's product pretty darn well. At higher que-depths, however, LSI's WarpDrive is the clear victor in this test.
|Custom File Transfer Tests|
|Our next series of tests are what you might call more "crude measurements" in that we simply fired up our trusty stop-watch and clocked the time it took to complete a copy and paste command of a single large file or a bunch of large files from one storage volume in our test system to another.
** Please note that we utilized a Fusion-io ioXterme card as our source drive in the following tests, to read files from or copy files to, for our read and write measurements. This affords us the luxury of much higher available bandwidth from the source drive or to a target drive, such that either direction would not be as much of a limiting factor in any given test condition.
Here times are tightly grouped at the top of the stack, with the OCZ RevoDrive 3 X2 taking more decisive edge versus the other PCI Express solutions in our test. With this test group, larger sequential transfers were noticeably faster on the OCZ RevoDrive 3 X2 especially.
|PCMark Vantage HDD|
|We really like PCMark Vantage's HDD Performance module for its real-world application measurement approach to testing. PCMark Vantage offers a trace-based measurements of system response times under various scripted workloads of traditional client/desktop system operation. From simple Windows start-up performance to data streaming from a drive in a game engine and video editing with Windows Movie Maker, we feel more comfortable that these tests reasonably illustrate the performance profile of SSDs in an end-user/consumer or workstation PC usage model.
This series of Vantage tests will stress mostly read performance in real-world usage models, with a broad mix of sequential and random read transactions of both small and large file sizes.
In terms of overall performance, the OCZ RevoDrive 3 X2 offered the best results here in these mostly read-intensive workload. The Gaming module in PCMark Vantage, for example, employs data decompression that is required in loading a compressed game level from the drive being tested. Another area where the RevoDrive 3 X2 shined was Windows Photo Gallery, where importing digital images into the application is the required workload. Both of these tests require larger sequential transfers, an area of strength for RevoDrive 3 X2. The only test where OCZ's new PCIe SSD lagged behind a touch was Vista start-up, where it couldn't quite catch the Fusion-io ioDrive. The caveat here is of course that Fusion-io's product is not bootable, so the datapoint holds a bit less weight with us as a result.
On a side note, that we did test the RevoDrive 3 X2 as a boot volume, just to see how snappy it was getting to a Windows 7 desktop. Unfortunately we were met with lack-luster results. OCZ informed us that this is because the drive is currently employing 32-bit drivers in Windows currently and our 64-bit installation was hampering performance. We were also assured that OCZ will be releasing full WHQL certified 64-bit drivers with the product when it ship to retail channels.
|PCMark Vantage HDD (Continued)|
|The following PCMark Vantage HDD tests are more write intensive and in some cases stress the Achilles' Heel of the average storage subsystem, that being random write performance.
Here again we see mostly decisive victories for OCZ's RevoDrive 3 X2, with only one marginal shortfall in the Application loading test, where Fusion-io's ioDrive squeaks out the top spot. Other than that, we see a sizable lead for the RevoDrive 3 in Windows Media Center and Movie Maker with a virtual draw versus the LSI WarpDrive in the Windows Media Player test.
|Performance Summary and Conclusion|
The OCZ RevoDrive 3 X2 took to our battery of synthetic and real-world benchmarks with surprising top-end performance in all but corner case test conditions (IOMeter workloads). Even then, OCZ's new PCI Express-based SSD offered very competitive results considering its dramatically lower cost and consumer-targeted MLC NAND Flash. The most impressive results we saw with the RevoDrive 3 X2 were in the ATTO and PCMark Vantage tests, where OCZ's new PCIe card handily outpaced even the super high-end Fusion-io ioDrive in all but a couple of tests.
Our early look at OCZ's RevoDrive 3 X2 PCI Express SSD is intended to give you a glimpse of the performance profile of the product, rather than a full-up evaluation. At this point in time, we've only been able to test early release prototypes and as such we can't firmly give you a rating here to go with either way on a buying decision or otherwise. However, what we have been able to ascertain from our time testing the product is that OCZ is definitely on track to deliver a very impressive PCI Express SSD solution in the RevoDrive 3 X2, in addition to laying the foundation for a powerful family of products based on their SuperScale storage accelerator and VCA 2.0 SSD controller virtualization technology.
OCZ's acquisition of Indilinx has apparently worked out well for them thus far. Though they won't confirm their SuperScale processor is at least part of the fruit of their labor of integrating Indilinx's IP into their portfolio, it certainly appears that way. And of course, the company's strong integration of SandForce controller technology is obviously a big part of their game plan moving forward as well.
Update 6/28/11 - 7:15PM - We have since learned through reports coming in from the readership that driver-level information (thanks to Anandtech for picking up on this) is pointing toward Marvell as the silicon source manufacturer of OCZ's SuperScale processor on the RevoDrive 3 X2. It's apparent that OCZ has had a significant hand in firmware development with this device, which is where the Indilinx Software Engineering team may have come into play perhaps. Though without firm confirmation from OCZ, this is all just speculation at this point in time.
We'll have to hold off for now at giving this prototype product from OCZ a formal HotHardware score. However, in the weeks ahead, you can expect the RevoDrive 3 X2 to hit retail. We're comfortably optimistic that OCZ will work out the current small power standby bug in the product and also deliver full 64-bit WHQL certified drivers soon. When that happens, Workstation and Content Creation professionals, performance enthusiasts and speed freaks will have yet another hugely impressive PCI Express SSD option to choose from and at price points that are actually approachable.