SandForce TRIM Issue & Corsair Force Series GS (240GB) Review
by Kristian Vättö on November 22, 2012 1:00 PM ESTThe Corsair Force GS
Now that the TRIM issue is out of the way, it's time to take a closer look at Corsair's Force GS SSD. Not much has happened in the SandForce SSD frontier for a while and the Force GS isn't exactly special either. As with most SandForce based SSDs, it's based on SandForce's SF-2281 controller, although Corsair has chosen SanDisk, a bit more uncommon choice, as the NAND supplier. SanDisk's NAND uses the same Toggle-Mode interface as Toshiba's and Samsung's NAND, which is rarer in SandForce SSDs than ONFi NAND. That's not to say that the Force GS is the first Toggle-Mode NAND based SandFroce SSD; there are quite a few that use Toggle-Mode NAND as well, such as OWC's Mercury 6G and Mushkin's Chronos Deluxe.
| Comparison of NAND Interfaces | ||||||
| ONFi | Toggle-Mode | |||||
| Manufacturers | IMFT (Intel, Micron, Spectec), Hynix | Toshiba/SanDisk, Samsung | ||||
| Version | 1.0 | 2.0 | 2.x | 3.0 | 1.0 | 2.0 |
| Max Bandwidth | 50MB/s | 133MB/s | 200MB/s | 400MB/s | 166MB/s | 400MB/s |
By using Toggle-Mode NAND, Corsair claims to achieve slightly higher write speeds than ONFi based SandForce SSDs, although the difference is only about 5MB/s in sequential write and 5K IOPS in 4K random write. While SanDisk NAND is quite rare, it should not be of lower quality than any other NAND. Toshiba and SanDisk have a NAND joint venture similar to Intel's and Micron's IMFT: SanDisk owns 49.9% and Toshiba owns the remaining 50.1% of the joint venture. As the NAND comes from the same fabs, there is no physical difference between SanDisk and Toshiba NAND, although validation methods may of course be different.
| Corsair Force Series GS Specifications | ||||
| User Capacity | 180GB | 240GB | 360GB | 480GB |
| Controller | SandForce SF-2281 | |||
| NAND | SanDisk 24nm Toggle-Mode MLC NAND | |||
| Raw NAND Capacity | 192GiB | 256GiB | 384GiB | 512GiB |
| Number of NAND Packages | 12 | 16 | 12 | 16 |
| Number of Die per Package | 2 | 2 | 4 | 4 |
| Sequential Read | 555MB/s | 555MB/s | 555MB/s | 555MB/s |
| Sequential Write | 525MB/s | 525MB/s | 530MB/s | 455MB/s |
| Max 4K Random Write | 90K IOPS | 90K IOPS | 50K IOPS | 50K IOPS |
The interesting thing in Force GS are the available capacities; Corsair isn't offering anything smaller than 180GB and there is also a more uncommon 360GB model included. As explained in our pipeline article of the Force GS launch, 180GB and 360GB models are achieved by running the SF-2281 controller in 6-channel mode and using either 6 or 12 NAND packages. Corsair only had 240GB review samples available, but they promised to send us a 360GB sample once they get them.
| Price Comparison (11/22/2012) | |||||
| 120/128GB | 180GB | 240/256GB | 360GB | 480/512GB | |
| Corsair Force GS | N/A | $160 | $220 | $315 | $400 |
| Corsair Force GT | $130 | $185 | $220 | N/A | $390 |
| Corsair Neutron | $120 | N/A | $213 | N/A | N/A |
| Plextor M5S | $110 | N/A | $200 | N/A | N/A |
| Crucial m4 | $110 | N/A | $185 | N/A | $389 |
| Intel 520 Series | $130 | $190 | $234 | N/A | $370 |
| Samsung SSD 830 | $104 | N/A | $200 | N/A | $550 |
| OCZ Vertex 3 | $89 | N/A | $200 | N/A | $425 |
| OCZ Vertex 4 | $75 | N/A | $160 | N/A | $475 |
| Mushkin Chronos Deluxe | $100 | N/A | $180 | N/A | N/A |
Force GS is priced competitively against other SSDs at all capacities. All capacities are priced noticeably below $1 per GB, even the not so common 180GB and 360GB models. Of course, it should be kept in mind that SSD prices change frequently (e.g. some of the models like the 480GB Vertex 3 have dropped in price by 30% or more in the past two months!), so you should do your own research before buying. We can only quote the prices at the time of writing, there is a good chance that our pricing table will be at least somewhat out of date in less than a week.
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FunnyTrace - Wednesday, November 28, 2012 - link
Yes, I did read an article on Tweaktown about this in August 2012.JellyRoll - Friday, November 23, 2012 - link
OMG...SandForce does not do dedupe (deduplication). It does not "has to check if the data is used by something else."!!The drive is unaware of the actual file usage above the device level. That is a host level responsibility.
I cannot believe that this article was not vetted before it was posted.
Kristian Vättö - Friday, November 23, 2012 - link
SandForce does deduplication at the device level. It doesn't look for actual files like the host does because it's all ones and zeros for the controller. However, what it does is look for similar data patterns.For example, if you have two very similar photos which are 5MB each, the controller may not write 10MB. Instead, it will only write let's say 8MB to the NAND because some of the data is duplicate and the whole idea of deduplication is to minimize NAND writes.
If you go and delete one of these photos, the OS sends a TRIM command that tells the LBA is no longer in use and it can be deleted. What makes SandForce more complicated is the fact that the photos don't necessarily have their own LBAs, so what you need to do is to check that the LBA you're about to erase is not mapped to any other LBA. Otherwise you might end up erasing a portion of the other photo as well.
JellyRoll - Friday, November 23, 2012 - link
I challenge you to offer one document that supports your assertion that sandforce does deduplication. There ins't any, as it does not. Feel free to link to the technical document to support your claims in your reply.SandForce supports compression, not deduplication.
Here is a link to documentation and product data sheets.
http://www.lsi.com/products/storagecomponents/Page...
Kristian Vättö - Friday, November 23, 2012 - link
SandForce/LSI has published very little about the technology behind DuraWrite and how it works, but a combination of technologies including compression and deduplication is what they have told us.http://www.anandtech.com/show/2899/3
JellyRoll - Friday, November 23, 2012 - link
Linking an Anandtech article is not proof that SandForce does deduplication. A quick Google will reveal that there is no other source, outside of Anandtech, that claims that they offer deduplication on the current series of processors.As a matter of fact, that article is the only other reference to deduplication and SandForce that can be found.
There was a mistake made in that article.
JellyRoll - Friday, November 23, 2012 - link
As a matter of fact, if deduplication were to apply to the SandForce series of processors then incompressible data would also experience decreases in write amplification. SandForce is very public that they have "top follow the same rules" with incompressible data as everyone else. IE, they suffer the same amount of write amplification.Since SandForce controllers only exhibit performance enhancing and endurance increasing benefits from compressible data, that alone indicates that deduplication is not in use.
Deduplication can be applied regardless of the compressibility of the data.
extide - Saturday, November 24, 2012 - link
Incompressible data generally doesnt have duplications in it... that's kinda what makes it incompressible... I mean the whole POINT of compression is removing duplications!JellyRoll - Saturday, November 24, 2012 - link
If you have two matching sets of data, be they incompressible or not, they would be subject to deduplicatioin. It would merely require mapping to the same LBA addresses.For instance, if you have two files that consist of largely incompressible data, but they are still carbon copies of each, they are still subject to data deduplication.
extide - Wednesday, November 28, 2012 - link
That could also be considered compression. Take 2 copies of the same MP3 file and put them into a zip file, how big is the zip file? Pretty close to the size of one copy...