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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iLLz - Monday, February 6, 2012 - link
There you go, being all logical and stuff.DanSmith - Tuesday, February 7, 2012 - link
+1kyuu - Monday, February 6, 2012 - link
So, Intel wants people to pay a huge price premium over drives with identical flash and an identical controller? For what? Some validation testing and a custom firmware? Despite the fact that they source their own flash giving them a price advantage over everyone except maybe Samsung? Please.Also, the 240GB is *more* than twice as expensive as as the 120GB? Why wouldn't you just buy two 120GB drives then? I doubt the performance difference is even worth noting, and once Intel's own new RST drivers come out that support passing the TRIM command to RAID arrays comes out, you can R0 them and get *better* performance than a single 240GB.
FunBunny2 - Tuesday, February 7, 2012 - link
*NOT* identical flash or controller. Anand spent much of the text explaining that.NitroWare - Wednesday, February 8, 2012 - link
Not sure if the PCB is completely custom or Intel just put their logo on a slightly modified circuit board - and then there is the Bill of Materials for the supporting components.Corsair have been claiming publicly they went with a custom PCB for their Force 3 and even put up oscilloscope eye diagrams to 'prove' that their signal integrity as superior to a generic reference PCB
Coup27 - Monday, February 6, 2012 - link
Anand, could you please update Bench with the 830 results? They appear to have been forgotten about adding into Bench.Narrlok - Tuesday, February 7, 2012 - link
I second this request. I was about to post about this as well since I wanted to compare the 830 with this drive.beginner99 - Monday, February 6, 2012 - link
Well it seems obvious especially also because of the delay that the general advice here is to not touch OCZ and especially Sandforce seems to be more than true. There obviously must be quite a lot of bugs in the sandforce firmware.But then the price premium? I don't see it. You can get a crucial m4 that preforms just as good and has a very good track record in terms of reliability. (ignoring this 5000 hr bug...but it doubt even intel would spot that)
While it is sure a fast and reliable drive, the m4 is too while costing much less. And the Samsung isn't bad either.
eman17j - Wednesday, February 8, 2012 - link
they fixed the 5000 hr bugeman17j - Wednesday, February 8, 2012 - link
Also the newer line ocz came out with uses the Indilix controller