Corsair Accelerator 60GB SSD Cache Drive Review

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As each generation of hard drives grew in capacity at a breakneck pace, storage space on spindle-based drives was rarely an issue. However, performance gains from one generation to the next have always been, at best, incremental. Now, with solid state storage in its ascendency, the opposite is true: SSDs offer massive performance but miniscule storage capacity relative to their cost. With the aptly named Accelerator 60GB cache drive, Corsair hopes to sell consumers on a solution that will give them the best of both technologies with none of the associated drawbacks.

Much like OCZ’s Synapse, the Corsair Accelerator relies on Nvelo’s Dataplex software to meld with the user’s existing hard drive into one “hybrid” storage solution. While this approach does require a certain amount of processor overhead, allowing the software to decide what gets cached on the speedy SSD and what can reasonably be tucked away on the slow-but-steady HDD has its merits. Namely, it allows for increased storage flexibility and performance while also keeping the associated hardware costs relatively low. As the Dataplex solution is fairly robust with only moderate CPU requirements, we have no concerns with Corsair’s decision to follow OCZ in this regard.

What is questionable is the actual solid state drive they have included as part of the bargain. Rather than using a Corsair Force 3 60GB for the Accelerator, Corsair has instead opted for their Nova Series 2 60GB drive. Unlike the competition, this drive uses the less capable SF-2181 controller. Furthermore, it has only the typical 7% overprovisioning found with the standard Nova Series 2 drives which could cause an issue for long term durability when used for caching purposes. This is completely different than OCZ’s Synapse series, which relies on a more capable, 100% over provisioned SF-2281-based Agility 3 60GB drive. With an online asking price of $90—or just ten dollars less than that of the Synapse 64GB—the Accelerator will have to be impressive if it hopes to overcome its potential limitations.

To keep things as fair as possible, we will be pairing the Accelerator with the same 1TB hard drive we tested the OCZ Synapse with. This will allow us to find out how much performance is possible from a truly budget setup and judge theAccelerator’s overall efficiency and effectiveness.

Compared to that of the OCZ Synapse, the Corsair Accelerator’s exterior is more robust and reassuring. While some SSD makers use a metal-and-plastic solution, the Accelerator’s outer shell is a full metal affair that seems like it could shrug off damage that would leave a Synapse in pieces.

Unfortunately, the interior architecture of the Accelerator is not as satisfying. Not only is the PCB half the size of what is normally found in SandForce-based devices, but so too is the number of NAND ICs greatly reduced. Whereas 16 dual-layer NAND modules are housed within most solid state drives, this model has only eight. This means that the density of the chips is higher than that of most contemporary 64GB SSDs. However, the Accelerator may not be able to take advantage of this moderate potential increase in performancefor the simple reason that (unlike any other SandForce-based drive we have reviewed to date) the Accelerator does not use an SF-2281 controller and relies instead on the slower and less capable SF-2181.

It is also unfortunate that Corsair—much like OCZ—opted for ONFi 1 NAND rather than ONFi 2 or Toggle-Mode NAND. Either of these superior NAND technologies should have allowed the Accelerator to avoid slipping into a degraded state over time.

It is also noteworthy that the software needed to actually run the Accelerator as intended is included neither in the box nor on the drive itself. Rather than bundle a CD with a potentially outdated version, Corsair simply supplies a serial number that can be used to download the Dataplex software.

 

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Testing Methodology

Testing Methodology

Testing a drive is not as simple as putting together a bunch of files, dragging them onto folder on the drive in Windows and using a stopwatch to time how long the transfer takes. Rather, there are factors such as read / write speed and data burst speed to take into account. There is also the SATA controller on your motherboard and how well it works with SSDs & HDDs to think about as well. For best results you really need a dedicated hardware RAID controller w/ dedicated RAM for drives to shine. Unfortunately, most people do not have the time, inclination or monetary funds to do this. For this reason our test-bed will be a more standard motherboard with no mods or high end gear added to it. This is to help replicate what you the end user’s experience will be like.

Even when the hardware issues are taken care of the software itself will have a negative or positive impact on the results. As with the hardware end of things, to obtain the absolute best results you do need to tweak your OS setup; however, just like with the hardware solution most people are not going to do this. For this reason our standard OS setup is used. However, except for the Windows 7 load test times we have done our best to eliminate this issue by having the drive tested as a secondary drive. With the main drive being a Kingston HyperX 240GB Solid State Drive.

For synthetic tests we used a combination of the ATTO Disk Benchmark, HDTach, HD Tune, Crystal Disk Benchmark, IOMeter, AS-SSD, Anvil Storage Utilities and PCMark 7.

For real world benchmarks we timed how long a single 10GB rar file took to copy to and then from the devices. We also used 10gb of small files (from 100kb to 200MB) with a total 12,000 files in 400 subfolders.

For all testing a Asus P8P67 Deluxe motherboard was used, running Windows 7 64bit Ultimate edition. All drives were tested using AHCI mode using Intel RST 10 drivers.

All tests were run 4 times and average results are represented.

In between each test suite runs (with the exception being IOMeter which was done after every run) the drives are cleaned with either HDDerase, SaniErase or OCZ SSDToolbox and then quick formatted to make sure that they were in optimum condition for the next test suite.

Please note:
Due to the unique nature of this hybrid setup certain tests have been omitted as they require an unformatted drive to test or gave erroneous results.

Processor: Core i5 2500
Motherboard: Asus P8P67 Deluxe
Memory: 8GB Corsair Vengeance LP “blue”
Graphics card: Asus 5550 passive
Hard Drive: Kingston HyperX 240GB, OCZ 480GB RevoDrive3 x2
Power Supply: XFX 850

SSD FIRMWARE (unless otherwise noted):
OCZ Vertex 2 100GB: 1.33
OCZ Vertex 3 MI 240GB: 2.1.5
OCZ Vertex 4 512GB:5.10.31
Corsair Force 3 GT 120GB: 1.3.3
Patriot Pyro 120GB: 3.3.2
Crucial M4 256GB: 0309
Mushkin Chronos 120GB: 3.3.2
Intel 520: 400i
OCZ Synapse:2.15
Corsair Accelerator: 1.3.4

 

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ATTO Disk Benchmark

ATTO Disk Benchmark

The ATTO Disk Benchmark tests the drive’s read and write speeds using gradually larger file sizes. For these tests, ATTO was set to run from its smallest to largest value (.5KB to 8192KB), and the total length was set to 256MB. The test program then generates an extrapolated performance figure in megabytes per second.

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Where the Accelerator relies on a SATA 2 SF-2182 controller, it comes as no surprise that the power curves are lower than those of a comparably priced OCZ Synapse 64GB drive. However, compared to the system running in HDD-only mode, the Accelerator’s results do speak for themselves and should correspond to a tangible boost in performance.

 

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Crystal DiskMark / PCMark 7

CrystalDiskMark

CrystalDiskMark is designed to quickly test the performance of your hard drives. Currently, the program allows you to set the number of test iterations to run as it measures sequential and random read/write speeds. We left the number of tests at five and the size at 100MB.[/

Once again the major bottleneck of the Accelerator is not the hard drive; rather, it is the sluggish solid state drive Corsair has opted to include. These results are very similar to what you would expect an ONFi 1-based SF-2281 drive to provide when limited to SATA 2 speeds. That being said, compared to what the included hard drive—or any hard drive for that matter—can offer, the performance boost is significant and indeed impressive.

PCMark 7

While there are numerous suites of tests that make up PCMark 7, only one is pertinent: the HDD Suite. This consists of numerous tests that attempt to replicate real-world drive usage. Everything from how long a simulated virus scan takes to complete, to MS Vista start-up time, to game load time is assessed in the core tests. However, since we don’t consider this anything other than just another synthetic benchmark, we have opted to include only the overall score and not the individual test results.

A difference of just under 100 points is not a disaster, but once again the blame for the Accelerator’s deficiencies rests solely on the shoulders of Corsair and their decision to use a lower end controller. While synthetic results do not give a great picture of real world performance, the reduction in throughput is hard to justify considering the negligible difference in price between it and the Synapse.

 

[AkG]

AS-SSD / Anvil Storage Utilities Pro

AS-SSD

AS SSD is designed to quickly test the performance of your drives. Currently, the program allows the measurement of sequential and 4K read/write speeds, as well as 4K read/write speeds at a queue depth of 6. While its primary goal is to accurately test SSDs, AS SSD does run on all storage mediums; it just takes a long time to run on mechanical drives, as each test reads or writes a full gigabyte of data.

Compared to what even a fast hard drive like the VelociRaptor can do in AS-SSD, these results are very good. However, they are still noticeably lower than what an OCZ Synapse can accomplish when in the same situation.

Anvil Storage Utilities Pro

Much like AS SSD, Anvil Pro was created to quickly and accurately test your drives. While it is still in beta stages, it is a versatile and powerful little program. Currently it can test numerous read and write scenarios, but two in particular stand out for us: 4K at a queue depth of 4, and 4K at a queue depth of 16. A queue depth of 4 along with 4K sectors can be equated to what most users will experience in an OS scenario, while a depth of 16 will likely be encountered only by power users or in enterprise workloads. We have also included the 4K queue depth 1 results to help put these other two numbers in perspective. All settings were left in their default states, and the test size was set to 1GB.

These results point to a rather obvious trend: the Corsair Accelerator will boost performance well beyond what a hard drive—even a 10,000 rpm drive—can offer, but this level of potential performance is lower than other similar solutions.

 

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IOMETER

IOMeter

Iometer is heavily weighted towards the server end of things, and since we here at HWC are more end-user-centric we will be generating and judging the results of Iometer a little bit differently. To test each drive we did five test runs per HDD (at 1, 4, 16, 64, and 128 queue depths). Each test has eight parts, and each part lasts 10 minutes with an additional 20-second ramp-up. The eight subparts are set to run 100% random, 80% read, 20% write and to test 512b, 1K, 2K, 4K, 8K, 16K, 32K,and 64K chunks of data. When each test is finished, Iometer spits out a report in which each subtest is given a score in I/Os per second (IOPS). We then take these eight values, add them together, and divide by 8. This gives us an average score for each particular queue depth that is more weighted toward a single-user environment.

With its only moderate software overhead, the Accelerator does a fairly decent job at our custom IOMeter tests. However, a hybrid solution would be a poor match for anything besides home environments. Even here,the SF-2181 controller is simply outclassed by SF-2281 controller based drives at all queue depths.

 

[AkG]

Windows 7 Start Up / Adobe CS5 Load Time

Windows 7 Start-Up with Boot Time A/V Scan Performance

When it comes to hard drive performance, there is one area that even the most oblivious user notices: how long it takes to load the operating system. Where Windows 7 has become nearly ubiquitous for solid state drive enthusiasts, we have chosen Windows 7 Ultimate 64-bit as our OS. In previous load time tests, we would use the anti-virus splash screen as our finish line; this however is no longer sufficient. We have not only added a secondary anti-virus tool to load on startup but also an anti-malware program. Super Anti-Spyware has been set to initiate a quick scan on Windows start-up, and the completion of the quick scan will be our new finish line.

It takes the Accelerator 15 seconds longer than the Synapse to boot and run the virus scan. While this isn’t a long time, we would be hard-pressed to justify this level of performance reduction for the sake of only a few dollars. The fact of the matter is that while its NAND internals are denser than an OCZ Synapse 60GB’s, the Accelerator is still being severely hobbled by the slower SF-2181 controller.

Adobe CS5 Load Time

Photoshop is a notoriously slow-loading program under the best of circumstances. The latest version actually shows a pretty decent improvement in load times, but when you add in a bunch of extra brushes and the like, you get a torture test that can bring even the best I/O subsystems to their knees.

The performance increase the Corsair Accelerator can offer over any hard drive is impressive, but it will be less than what similarly priced Nvelo/SandForce hybrid solutions bring to the table.

 

[AkG]

Firefox Offline / Real World Data Transfers

Firefox Portable Offline Performance

Firefox is known for being slow at loading tabs in offline mode once the number of pages grows larger than a dozen or so. We can think of few scenarios more taxing than having 100 tabs set to reload on Firefox startup, but this is exactly what we have done here.

By having 100 pages open in Firefox portable, setting the browser to reload the last session upon next session start, and then setting it to offline mode, we are able to recreate a worst case scenario. Since we are using Firefox portable all files are easily positioned in one location, making it a simple matter to repeat the test as necessary. In order to ensure repeatability, before touching the Firefox portable files, we have backed them up to a .rar file and then extracted it to the test device.

The results are—once again—much improved over what a hard drive alone can provide, but the performance is lower than that of the OCZ Synapse. Corsair may indeed have tried to mask the reduction in controller performance with higher density NAND, but if so they weren’t quite successful. We do feel comfortable in saying they would have had much better results if they had opted for Toggle-Mode NAND ICs instead of ONFi 1.

Real World Data Transfers

No matter how good a synthetic benchmark like Iometer or PCMark is, it can’t tell you how your hard drive will truly perform in “real world” situations. All of us here at Hardware Canucks endeavor to give you the best, most complete picture of a review item’s capabilities. To this end we will be running timed data transfers to give you a general idea of how benchmark performance relates to real-life use. In our Large File Copy test, we transfer a 10GB contiguous file. Our Small File Copy test transfers a folder containing 400 subfolders with a total 12,000 files varying in length from 200MB to 100KB (10GB total).

Testing will include transfer to and from the devices using MS RichCopy (set to 1 file depth) and logging the overall performance. Here is what we found.

As with all other tests performed on the Corsair Accelerator, the results are decent, but they do not indicate as much of an improvement over platter-based storage as the competition offers.

 

[AkG]

NON-TRIM Environment Testing

Non-TRIM Environment Testing

Any Sandforce controller can be severely handicapped in an environment that doesn’t support TRIM. To re-create this, we first modified our test-bed so that it would not pass the necessary cleaning commands to the drive. Meanwhile, to artificially induce a degraded state, we run eight hours of Iometer (100% random, 100% write, 4K chunks of data, QD=64) across the entire array’s capacity. At the end of this test, the Iometer file is deleted and the drive is then tested. This method, the results of which are indicated below as “Dirty,” will replicate drive performance after extended heavy writing before any self-maintenance routines kick in.

In order to activate each drive’s garbage collection routines, we then let the system idle for 30 minutes and rerun the tests.

Real World Results

For a real world application we have opted for our standard Vista load time test.

While it is very unlikely you will ever hammer your Corsair Accelerator as hard and as fast as we have, the lack of overprovisioning is going to have a negative and noticeable impact on the long-term performance of this drive. You may be getting twice the “room” of an OCZ Synapse 64GB—60B vs. 30GB—but this increase in capacity is coming at the direct expense of throughput as the SSD is inevitably written and re-written to over time. Considering that this drive does not exactly have performance to burn, what this means is that you are much more likely to notice slowdowns with this setup than you would with an OCZ Synapse or any other similarly over provisioned hybrid setup.

 

[AkG]

Corsair Accelerator and CPU Utilization

The Corsair Accelerator and CPU Utilization

Since the Corsair Accelerator’s caching routinesarebased on software rather than hardware, higher CPU utilization is to be expected. Whether the software is demanding enough to affect overall responsiveness is the question.

To obtain an accurate picture of how much CPU horsepower this device truly requires, we have configured the Accelerator as a secondary data drive and let the system idle with a minimal number of processes running. Using Windows' built in Performance Monitor we can see exactly how much processing power is being dedicated to a given storage solution. Lastly, we run CrystalDiskMark while monitoring CPU utilization.

The processor is a Core i5 2500K running at stock speed.

Since both the OCZ Synapse and Corsair Accelerator rely on the exact same Nvelo Dataplex software, it comes as no surprise that the CPU utilization is very similar in both cases. With an idle in the low 20s and an average usage rating in the 30s—with a peak of around 68%—this hybrid solution is unlikely to cause a CPU bottleneck in any modern computer system. Older quad core systems should also have power to spare. Only an aging system like an AMD Athlon X2 3800 will have any issues with the demands the Accelerator places upon it.