Intel SSD 520 Review: Cherryville Brings Reliability to SandForce
by Anand Lal Shimpi on February 6, 2012 11:00 AM ESTPerformance Over Time & TRIM
SandForce's controllers have always behaved poorly if you pushed them into their worst case scenario. Should you fill a SF-2281 based drive completely with incompressible data then continue to write to the drive with more incompressible data (overwriting some of what you've already written) to fill up the spare area you'll back the controller into a corner that it can't get out of, even with TRIM. It's not a terribly realistic situation since anyone using an SF-2281 SSD as a boot drive will at least have Windows (or some other easily compressible OS) installed, and it's fairly likely that you'll have other things stored on your SSD in addition to large movies/photos. Regardless, it's a corner case that we do have to pay attention to.
I was curious to see if Intel's firmware did anything differently than the standard SandForce build used by other partners. To find out I took an Intel SSD 520 (240GB) and a Kingston HyperX (SF-2281 240GB) and filled both drives with incompressible data. I then ran a 60 minute 4KB random write torture test (QD32), once again, with incompressible data. Normally I'd use HDTach to chart performance over time however HDTach measures performance with highly compressible data so we wouldn't get a good representation of performance here. Instead I ran AS-SSD to get a good idea for incompressible sequential performance in this worst case state. Afterwards, I TRIMed the drives and ran AS-SSD again to see if TRIM could recover the drive's performance.
| Intel SSD 520 - Resiliency - AS SSD Sequential Write Speed - 6Gbps | |||||
| Clean | After Torture | After TRIM | |||
| Intel SSD 520 240GB | 284.5 MB/s | 162.9 MB/s | 162.9 MB/s | ||
| Kingston HyperX 240GB | 289.3 MB/s | 162.5 MB/s | 162.5 MB/s | ||
Surprisingly enough, Cherryville doesn't actually perform any differently than the stock SandForce firmware in this case. SandForce definitely improved the worst case scenario performance with the SF-2281 compared to the first generation controller, and it also improved performance compared to earlier builds of the 2281 firmware, but Intel appears to have not done anything above and beyond here. Based on these results I'd be willing to bet that Intel doesn't have source code access to the SF-2281 firmware otherwise it would've worked on a solution to this corner case. Performance in this worst case scenario isn't terrible but the fact that it's irrecoverable even after a TRIM is what's most troubling. Again, I don't see most end users backing themselves into this corner but it's worth pointing out.
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hugh2323 - Monday, February 6, 2012 - link
Some posters are missing the reason why this drive has a high premium. It is intented for the market that values reliability over price. This market considers the price of lost data to be higher than the premium of the drive. If you are a business, and a computer goes down with its data, the lost hours of productivity and cost of data loss can easily add up. Compared to paying 20% extra for the drive initially (or whatever it is), is chump change compared to that.And then there is the consumer market that doesn't have time to f*** around with blue screen of death and whose purse strings perhaps aren't so tight.
So if you don't want to pay the premium, then your not in the target market. Simple as that.
neotiger - Monday, February 6, 2012 - link
... except this SSD doesn't give you reliability.It doesn't have any capacitors, which means after a computer crash or a power outage you will lose your data.
Not exactly reliable.
eman17j - Wednesday, February 8, 2012 - link
ssd are nonvolatile memory how are you going to lose all your data?eman17j - Wednesday, February 8, 2012 - link
oops I spoke to soon I know what you mean it wouldnt have the power to finish any write operation if there was an crash or power outage thereby losing your databji - Wednesday, February 8, 2012 - link
Irrelevant. Any application can make a sync call to ensure the data is written to the flash as necessary. Any application which does not make this sync call is risking the data at multiple levels of write cache before it actually makes it to the flash, so a capacitor would reduce the window of opportunity for data loss only slightly. And if you care that much about data loss, you are using sync anyway at that point of the application.eman17j - Wednesday, February 8, 2012 - link
buy an upsJediron - Tuesday, February 7, 2012 - link
Since when are MLC based SSD's more reliabele then SLC based SSD's ?Sorry, if they intended to put these SSD's in the market for endurance and reliability they make a mistake.
FunBunny2 - Tuesday, February 7, 2012 - link
bingo. but they last used SLC in the X25-E, and even Texas Memory is switching to MLC. The vendors are convinced they can get through warranty period with MLC. Unlike a HDD, which can last pretty much forever if it makes it through infant mortality, an SSD will die when it's time is up (think "Blade Runner").bji - Wednesday, February 8, 2012 - link
Theoretically, the failure mode for completely worn out flash should be that the drive can no longer be written to, but every existing block can still be read from. Thus you would not lose any data, you'd simply have to buy a new drive and clone the old one to it.In practice, it seems like either most SSD failures are not in the flash (maybe they are the result of firmware bugs that wedge the on-disk structures into an unrecoverable state?), or that if they are in the flash most firmware do not handle such failures gracefully and instead of putting the device into a read-only recoverable mode just give up and die. This is after reading many, many reports of SSD failures where the device became completely inoperable instead of going into read-only mode.
Also I've had plenty of platter HDD failures over the years, I always found them to be the least reliable component of any computer (ok, I guess fans are less reliable, but fan failure usually isn't catostrophic and is easy to fix; also power supplies die pretty frequently and finally for some reason CD/DVD drives also seem to fail disturbingly often).
beginner99 - Tuesday, February 7, 2012 - link
I disagree. It is too late to the market. the crucial m4 has proven its reliability in the real world and the intel drive has no special reliability features. And IMHO real world usage beats any validation tests intel can do.If you value your data you would have to back it up anyway, regardless of which drive you use.
m4: never heard of BSOD issues.
While I agree that sandforce drives have issues, there are others that do not and are also cheaper. The m4 is way best value. It's similar to CPUs. It is basically impossible to recommend any Desktop AMD CPU in any price or performance category. Same for SSD but here it is not possible to recommend Intel anymore.Neither for price, performance or reliability.