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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Sunburn74 - Monday, February 6, 2012 - link
A short, but more indepth article on your findings concerning the BSOD bugs afflicting the Sandforce ssds would be well appreciated by many. The findings of a tech supergenius like yourself would help dispel all the quackery that is floating about concerning what causes it and what doesn't and ultimately will help us all.Shadowmaster625 - Monday, February 6, 2012 - link
"The first possibility is that SandForce has been made aware of flaws in its current firmware and chooses against (or is legally prevented from) disclosing it to its partners"In other words, Intel is possibly forcing a company to sell knowingly defective product to its competitors. That is exactly the type of criminality that I would expect from intel. If this is true then it should be another billion dollars at some point, probably 8 years from now.
Rick83 - Tuesday, February 7, 2012 - link
I don't see any "forcing to sell" happening.I do see in-house development not being given away for free, which is normal business behavior. I'm pretty sure, for the right price, Intel would be willing to share the information.
In fact, the problem lies entirely with SandForce and the people blindly using their firmware, without doing the testing. Yes it's cheaper in the short run, but if you have to deal with a bunch of returns and your name being sullied, it may not pay off.
Also, I remember OCZ having an excllusive deal with SandForce at the start, where they were getting preferential treatment with regards to patches - that's criminal too?
DanSmith - Monday, February 6, 2012 - link
Great article thanks. The documentation on the 520 states it supports AES FDE but judging from my experience with other SF based drives it can be extremely hit and miss, with OCZ for example telling customers on their forum not to use it as it can permanently damage drives!!I hope to read more about AES on the 520 in the real world when you cover SSD's and enterprise soon.
Cheers, Dan
Beenthere - Monday, February 6, 2012 - link
Even after "extensive validation" of their own SSD controller Intel had Bugs and had to issue a firmware update to fix it. I'm not going to be so sure that the SF controller validation is any better than Intel's controller until the 520 series drives have been out in the field for 18-24 months.FunBunny2 - Monday, February 6, 2012 - link
-- until the 520 series drives have been out in the field for 18-24 months.Given the rate of change in SSDland, there'll likely not be any 520s for sale in that time frame.
Beenthere - Tuesday, February 7, 2012 - link
Then it's probably smart to let the guinea pigs suffer thru yet another half-baked SSD instead of wasting our time and money to be unpaid Beta testers for negligent SSD makers. Anand was correct: WAIT 6-12 months to see if they sort out most of the Bugs... He may need to extend that time frame to 36-48 months?As you can see from the numerous comments here, the 520 already has one or more BSOD reports at Intel's support site and people with OCZ and other drives still have issues even after the SandFarce firmware updates. On-The-Job-Training seems to be the current SSD strategy for most if not all SSD companies... which IMO is a disgrace.
FunBunny2 - Wednesday, February 8, 2012 - link
I'm no fan of SF. It's only that SSD land is vastly different from HDD land.FelixO - Monday, February 6, 2012 - link
Hi,I am very tempted to get one of these because I want to shove it in a machine and forget about it for 5 years (rather than upgrade regularly).
However the performance after being filled up is pretty worrying since that it something I do all the time!
Anand, in your SSD reviews you used to talk about what % of the disk was reserved space to help with avoidance of write amplification, or to assist with wear-levelling (or something like that!). You also used to say whether formatting the disk or doing a secure-erase would get you back to peak performance.
You seem to have omitted these discussions from recent reviews.
Any comments on those issues for this drive (Or the Samsung 830)?
Is it possible to adjust the reserved area on these drives? Will that mitigate the problems associated with completely filling the drives? Any comments on running these drives under Linux?
Thanks
4G92 - Monday, February 6, 2012 - link
Can anyone (Anand?) confirm if the Vertex 2 drives have this same Sandforce bug? I know the controllers are different, but my symptoms are EXACTLY the same.I just replaced my Vertex 2 with a Crucial M4 and the problems have now stopped, so I suspect the OCZ drive is the cause of the lockups...