Corsair Force Series GT 120GB SSD Review

[AkG]

Not that long after Corsair’s announcement of the Force Series 3 lineup of SSDs the Froce GT series was introduced. In order to keep up with the competition, the GT uses the same SF-2281 backbone as its sibling but packs higher performance ONFi 2 NAND to bring it in line with the enthusiast market’s expectations.

The Corsair Force GT is currently available in 60GB, 120GB and 240GB capacities while pricing runs the gamut from about $200 to well above the $400 mark. For the purposes of this review, we’ll be looking at the 120GB version which currently retails for approximately $275 and can be considered a competitor to OCZ’s Vertex 3 120GB.

Up until now our SATA 3 SSD reviews have mostly focused upon the crème de la crème 240GB versions. This unfortunately does have a tendency to skew the results upwards when people try to extrapolate the performance of lower capacity drives based on our charts. But this drive will allow us to finally answer the question many of you have been asking: how do the high performance SF2281 120GB drives compare to their 240GB counterparts?

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In order to better illustrate the Force GT’s performance on a more visceral level, Corsair decided to go with a screaming red and deep black two-tone colour scheme. If you want a solid state drive that can be shown off and be the centerpiece of your system, this is the one you’ve probably been waiting for.

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Opening up the Force GT 120GB we can see that besides the SF2281 controller the only other chips are the NAND modules. To be more specific all 16 slots are filled with eight chips (in two rows of four chips) per side. The ICs used in this drive are synchronous, 25nm Micron branded 29F64G08CBAAB ONFi 2 NAND which happen to be the reason behind the GT’s performance increase over the standard Force 3. This is the same NAND which can be found in many other high performance SF2281-based SSDs.

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As with the previous generation, the Force GT comes with a 2.5” to 3.5” drive bay adapter and the usual mounting hardware.

 

[AkG]

Introducing the SandForce SF2000 Family

Introducing the SandForce SF2000 Family

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As you are probably well aware by now, there are actually many different models which make up the next generation of SandForce controllers. Much like Intel’s socket 1155 i3/i5/i7 series of processors, all these different SandForce numbers represent slightly different tweaks and features, but all are basically built upon the same SF2000 foundation.

In grand total there are eight SF2000 iterations, but for the most part we won't see most of them in the retail channel. Take for example the SF2141; this is a cut down 4 channel, 24bit RS ECC, SATA 3GB/s controller which probably wont see much fan fare outside of truly budget SSDs. The easiest way to think about this one is to consider it the low end of SF2000 drives. Stepping up a level to 8 channels (and 55bit BCH ECC) but still SATA 3GB/s only is the SF2181 which you can consider the mid range of this generation. This one will probably be featured in more mid-tier next generation SSDs as it has better error correction abilities, yet cannot directly compete with the true stars of the SF200 consumer line: the SF 2281.

The only difference between the two “real” consumer grade SF2000 SATA 6G controllers most likely to be seen (the SF2281 and SF2282) is the one -the 2282- is only for extra large 512GB and higher drives (though the SF2281 can handle 512GB of NAND) and is a larger chip. These are the two flagship products as such have received all the features and all the tweaks which are going to become synonymous with the SF2000 consumer class controllers.

The other four controllers are for enterprise environments and boast features such as eMLC compatibility, Military Erase, SAS and super capacitor capabilities.

Features

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The SF2000 controller series is built upon the same architecture as the original SF1000 series. You get DuraWrite, RAISE and all the other features but these have all undergone enhancements and tweaking.

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The original SF1000 series had ECC of 24bits per 512byte sector of ECC; whereas the new controller has 55bits. The type of ECC has changed as well. The original used the more simplistic Reed-Solomon (aka “RS”) ECC code which is probably best known from its use in CDs.

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Compare and contrast this with the fact that the new controller uses Bose-Chaudhuri-Hocquenghem (aka “BCH”) for its ECC code; which is a more elegant version that targets individual errors. It is also faster and easier for the controller to correct these errors making for a lowered performance impact. AES encryption has also doubled from 128 to 256

The most important of these new features for consumers is of course the new SATA 6Gb/s capabilities. This larger bus instantly translates into much higher sequential performance. The second generation of flagship SandForce controllers has also received a boost on the small file performance end of things thanks in no small part to a 20% increase in IOPS. The first generation SF1200 was rated for up to 50,000 IOPS whereas the new controller family has a rating of 60,000 IOPS.

The other interesting feature which all but the most basic of the SF2000 models boast is SLC NAND abilities. In the past, a manufacturer had to step up the enterprise SF1500 to get SLC compatibility but now they don't have to. Add in lowered power consumption and you can see that while the SF2000 series builds upon the same basic foundation as the previous generation, they are not all that similar when you take a closer look.

 

[AkG]

A Look at DuraWrite, RAISE and More

A Look at DuraWrite, RAISE and More

Let’s start with the white elephant in the room and explain why this 120GB drive is in reality a 120GB drive. The Force GT has sixteen 8GB NAND chips onboard which gives it a capacity of 128GB, but is seen by the OS as 120GB. Manufacturers use this to help increase IOPS performance and also extend life via wear leveling (as there are always free cells even when the drive is reported as “full”) and even durability since the drive has cells in reserve it can reassign sectors to as the “older” cells die. While 8GB worth of cells set aside for a SandForce drive is not that much compared to some previous models, this is still a lot of space.

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As we said, over-provisioning is usually for wear leveling and ITGC as it gives the controller extra cells to work with for keeping all the cells at about the same level of wear. However, this is actually not the main reason SandForce sets aside so much. Wear leveling is at best a secondary reason or even just a “bonus” as this over-provisioning is mainly for the Durawrite and RAISE technology.

Unlike other solid state drives which do not compress the data that is written to them, the SandForce controller does real time loss-less compression. The upside to this is not only smaller lookup tables (and thus no need for off chip cache) but also means less writes will occur to the cells. Lowering how much data is written means that less cells have to be used to perform a given task and this should also result in longer life and even fewer controller cycles being taken up with internal house cleaning (via TRIM or ITGC).

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Longevity may be a nice side effect but the real purpose of this compression is so the controller has to use fewer cells to store a given amount of data and thus has to read from fewer cells than any other drive out there (SandForce claims only .5x is written on average). The benefit to this is even at the NAND level storage itself is the bottleneck for any controller and no matter how fast the NAND is, the controller is faster. Cycles are wasted in waiting for data retrieval and if you can reduce the number of cycles wasted, the faster an SSD will be.

Compressing data and thus hopefully getting a nice little speed boost is all well and fine but as anyone who has ever lost data to corruption in a compressed file knows, reliability is much more important. Compressing data means that any potential loss to a bad or dying cell (or cells) will be magnified on these drives so SandForce needed to ensure that the data was kept as secure as possible. While all drives use ECC, to further ensure data protection SandForce implemented another layer of security.

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Data protection is where RAISE (Redundant Array of Independent Silicon Elements) comes into the equation. All modern SSDs use various error correction concepts such as ECC. This is because as with any mass produced item there are going to be bad cells while even good cells are going to die off as time goes by. Yet data cannot be lost or the end user’s experience will go from positive to negative. SandForce likes to compare RAISE to that of RAID 5, but unlike RAID 5 which uses a parity stripe, RAISE does not. SandForce does not explicitly say how it does what it does, but what they do say is on top of ECC, redundant data is striped across the array. However, since it is NOT parity data there is no added overheard incurred by calculating the parity stripe.

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According to SandForce’s documentation, not only individual bits or even pages of data can be recovered but entire BLOCKS of data can be as well. So if a cell dies or passes on bad data, the controller can compensate, pass on GOOD data, mark the cell as defective and if necessary swap out the entire block for a spare from the over-provisioning area. As we said, SandForce does not get into the nitty-gritty details of how DuraWrite or RAISE works, but the fact that it CAN do all this means that it most likely is writing a hash table along with the data.

SandForce is so sure of their controller abilities that they state the chances of data corruption are not only lower than that of other manufactures’ drives, but actually approaches ZERO chance of data corruption. This is a very bold statement, but only time will tell if their estimates are correct. In the mean time, we are willing to give the benefit of the doubt and say that at the very least data corruption is as unlikely with one of these products as it is on any modern MLC drive.

 

[AkG]

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 testbed 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 Vista 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 Phoneix Pro 120GB Solid State Drive.

For synthetic tests we used a combination of ATTO Disk Benchmark, HDTach, HD Tune, Crystal Disk Benchmark, IOMeter, AS-SSD and PCMark Vanatage.

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 (or Vista for boot time test). 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.


Processor: Core i5 2400
Motherboard: Asus P8P67 Deluxe
Memory: 8GB Mushkin DDR3 1300
Graphics card: Asus 5550 passive
Hard Drive: 1x Seagate 3TB XT, OCZ 120GB RevoDrive
Power Supply: XFX 850


SSD FIRMWARE (unless otherwise noted):

OCZ Vertex: 1.6
OCZ Vertex 2 100GB: 1.33
Mushkin Callisto Deluxe 40GB: 3.4.0
Corsair Force F90: 2.0
OCZ Vertex 3 240GB: 1.11
Crucial C300 128GB: 006
Corsair Force 3 GT 120GB: 1.2

 

[AkG]

Read Bandwidth / Write Performance

Read Bandwidth

For this benchmark, HDTach was used. It shows the potential read speed which you are likely to experience with these hard drives. The long test was run to give a slightly more accurate picture. We don’t put much stock in Burst speed readings and thus we no longer included it. The most important number is the Average Speed number. This number will tell you what to expect from a given drive in normal, day to day operations. The higher the average the faster your entire system will seem.

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While lower than the 240GB iterations, the average sequential read speed of the Corsair Force 3 GT is still more than impressive. An average speed of basically 490MB/s may be 22MB/s less than the best we have seen, but it is still very, very fast. If all you plan on using your SSD for is loading games or other large file sequential operations the 120GB is just as good as the 240GB; albeit, with only half the storage capacity.

Write Performance

For this benchmark HD Tune Pro was used. To run the write benchmark on a drive, you must first remove all partitions from that drive and then and only then will it allow you to run this test. Unlike some other benchmarking utilities the HD Tune Pro writes across the full area of the drive, thus it easily shows any weakness a drive may have.

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It seems that much like with sequential read performance, when it comes to sequential write speed, this drive is very quick. With less than 7MB/s (average speed) - or less than 2% - separating this 120GB from a 240GB, the difference on sequential performance really can be considered negligible.

 

[AkG]

ATTO Disk Benchmark

ATTO Disk Benchmark

The ATTO disk benchmark tests the drives read and write speeds using gradually larger size files. For these tests, the ATTO program 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 spits out an extrapolated performance figure in megabytes per second.

<img src="http://images.hardwarecanucks.com/image/akg/Storage/Force3_GT_120/atto_w.jpg" border="0" alt="" />

<img src="http://images.hardwarecanucks.com/image/akg/Storage/Force3_GT_120/atto_r.jpg" border="0" alt="" />
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Sadly, this is the first indication of what is most likely going to be a trend for the Force GT 120GB: greatly reduced power curves at all but the high end of things. The small file curves of this drive are down right anemic when compared to the 240GB iteration of a SF2281 drive. With that being said, performance is certainly nothing to sneeze at.

 

[AkG]

Crystal DiskMark / PCMark Vantage

Crystal DiskMark

Crystal DiskMark is designed to quickly test the performance of your hard drives. Currently, the program allows to measure sequential and random read/write speeds; and allows you to set the number of tests iterations to run. We left the number of tests at 5 and size at 100MB.

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As with ATTO, we are seeing a noticeable difference in performance between the different capacities when it comes to 4k read and write speeds. While the 4K single que depth read and write performance is very admirable (with only basically a 2MB/s to 4MB/s performance drop) the same can't be said of deeper que depths. With the 32 que depth 4k results what was a minor disparity becomes downright large.

On the positive side, these numbers are still much better than the last generation's “flagship” SandForce based drives. If you have never experienced an SF2281 drive being powered by ONFi 2 or Toggle Mode 1.0 NAND these numbers will not fail to impress.

PCMark Vantage

While there are numerous suites of tests that make up PCMark Vantage, only one is pertinent: the HDD Suite. The HDD Suite consists of 8 tests that try and 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 tested in these 8 core tests; however we do not consider this anything other than just another suite of synthetic tests. For this reason, while each test is scored individually we have opted to include only the overall score.

<img src="http://images.hardwarecanucks.com/image/akg/Storage/Force3_GT_120/vantage.jpg" border="0" alt="" />
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While the sequential numbers are shaping up to be a best case scenario and the Crystal DiskMark being worst case, PCMark seems to take a more middle of the road approach to the GT. While a drop of nearly 5000 points is significant, a score of over 62,000 can be considered nothing but impressive. This is a massive boost compared to what a last generation 120GB drive was capable of doing and as such the Corsair Force 3 GT 120GB has nothing to be ashamed about.

 

[AkG]

AS-SSD / Access Time

AS-SSD

AS-SSD is designed to quickly test the performance of your drives. Currently, the program allows to measure sequential and small 4K read/write speeds as well as 4K file speed at a queue depth of 6. While its primary goal is to accurately test Solid State Drives, it does equally well on all storage mediums it just takes longer to run each test as each test reads or writes 1GB of data.

<img src="http://images.hardwarecanucks.com/image/akg/Storage/Force3_GT_120/asd_r.jpg" border="0" alt="" />

<img src="http://images.hardwarecanucks.com/image/akg/Storage/Force3_GT_120/asd_w.jpg" border="0" alt="" />
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As with Crystal DiskMark, AS-SSD uses incompressible data and as such it is not as forgiving as some other synthetic tests for mid-sized drives. The 4K difference between the 240gb and 120GB versions of the SF2281 varies from minor to moderate. In both read and write scenarios the performance is actually slightly worse than the best of what the last generation had to offer.

It also appears that the differences between the 120 and 240GB model really do get more extreme as the que depth gets higher. With a que depth of 64 the 120GB model is simply outclassed by the 240GB version. Luckily, there are going to be very few instances where consumers in a non-server environment are going to encounter such deep ques.

Access Time

To obtain an accurate reading on the read and write latency of a given drive, AS-SSD was used for this benchmark. A low number means that the drive’ data can be accessed quickly while a high number means that more time is taken trying to access different parts of the drive.

<img src="http://images.hardwarecanucks.com/image/akg/Storage/Force3_GT_120/random.jpg" border="0" alt="" />
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When it comes to read latency the difference between the 120GB and 240GB drives is so small, it falls well within error tolerances but the same can't be said of write latency. While a difference of 0.10 of a millisecond doesn't sound like all that much, it is more than enough to make the write latency worse than the last generation's flagship drives. This however, really is splitting hairs and it is truly doubtful anyone would notice such a small difference.

 

[AkG]

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 setting and judging the results of IOMeter a little bit differently than most. To test each drive we ran 5 test runs per HDD (1,4,16,64,128 que depth) each test having 8 parts, each part lasting 10 min w/ an additional 20 second ramp up. The 8 subparts were set to run 100% random, 80% read 20% write; testing 512b, 1k, 2k,4k,8k,16k,32k,64k size chunks of data. When each test is finished IOMeter spits out a report, in that reports each of the 8 subtests are given a score in I/Os per second. We then take these 8 numbers add them together and divide by 8. This gives us an average score for that particular que depth that is heavily weighted for single user environments.

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The IOMeter results posted by the Corsair Force 3 GT 120GB really do sum it up our synthetic results quite well. This drive is much more powerful than what was available to consumers in the last generation, but the gap between it and a 240GB SF2281-based drive is just as significant. When is “fast” not “fast enough”? Only you can answer that question, but let’s see what real world scenarios have to say about the Force 3 GT.

 

[AkG]

Vista Start Up / Adobe CS5 Load Time

Vista Start Up

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. While all the other tests were run with a Windows 7 operating system, this particular test uses another older test bed's “day to day” OS (copied over to our new testbed) which has accumulated a lot of crud over the months from installs and removals. We chose the Anti-Virus splash screen as our finish line as it is the last program to be loaded on start up.

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While a SIX second decrease in load time compared to the Vertex 2 is impressive, this posting is a full FIVE seconds slower than what some previously reviewed 240GB drives can accomplish. It seems that the 120GB versions maybe be “slower” than the 240GB iterations, but using words like “slow” in the same sentence as this drive would be extremely fallacious of us. The GT is fast, it just is not as fast as a much more expensive 240GB drive based off of the same controller.

Adobe CS5 Load Time

Photoshop is a notoriously slow loading program under the best of circumstances, and while the latest version is actually pretty decent, when you add in a bunch of extra brushes and the such you get a really great torture test which can bring even the best of the best to their knees. Let’s see how our review unit faired in the Adobe crucible!

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Once again, we are seeing the Corsair Force 3 GT 120GT split the difference between the 240GB drives and what the best of the last generation can do. Once again, an improvement of three seconds is significant; it is just that the 240GB models we have looked at already steal most of the 120’s thunder.