The SSD Anthology: Understanding SSDs and New Drives from OCZ
by Anand Lal Shimpi on March 18, 2009 12:00 AM EST- Posted in
- Storage
The Verdict
There’s no skirting the issue: even the best SSDs lose performance the more you use them. Eventually their performance should level off but what matters the most is how their performance degrades.
In using the X25-M I’d say that the performance drop was noticeable but not a deal breaker - and the data tends to agree with me. With average write latencies still well under 1ms, the drive maintained its most important performance characteristic - the ability to perform random accesses much faster than a conventional hard drive.
Keep in mind that with the cost per GB being as high as it is, these SSDs aren’t going to be used for large file storage in a desktop or notebook. You’re far more likely to use one as your boot/applications drive. As such, what matter the most aren’t peak transfer rates but rather fast access times. On a well designed drive with a good controller, peak transfer rates may fall over time, but latency remains good.
You end up with a drive that still manages to be much faster than the fastest 3.5” hard drives, but slower than when you first got it.
If, however, you aren’t ok with the performance drop over time then it’s worth considering what your options will be. When drives ship with ATA-TRIM support, hopefully late this year, they will do a better job of staying closer to their maximum performance. But the problem won’t be solved completely. Instead, what we’ll need to see is a more fundamental architectural change to eliminate the problem.
I still believe that a SSD is the single most effective performance upgrade you can do to your PC; even while taking this behavior into account. While personally I wouldn’t give up a SSD in any of my machines, I can understand the hesitation in investing a great deal of money in one today.
Intel’s X25-M: Not So Adaptive Performance?
The Intel drive is in a constant quest to return to peak performance, that’s what its controller is designed to do. The drive is constantly cleaning as it goes along to ensure its performance is as high as possible, for as long as possible. A recent PC Perspective investigation unearthed a scenario where the X25-M is unable to recover and is stuck at a significantly lower level of performance until the drive is secure erased once more.
There’s not much I can say about the issue other than I’ve been working with Intel on it very closely and it’s not something I’m overly concerned about at this point. I can replicate the PC Perspective data but not by using my machine normally. Through the right combination of benchmarks I can effectively put the drive in a poor performance state that it won’t recover from without a secure erase. I should also mention that I can do the same to other drives as well.
I’ll be able to say more soon but for now just hang tight. I’d venture a guess that Intel would not leave its most loyal customers out in the cold after spending $400 - $800 on a SSD. I can’t speak for Intel but like I said, stay tuned.
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blackburried - Wednesday, March 25, 2009 - link
It's referred to as "discard" in the kernel functions.It works very well w/ SSD's that support TRIM, like fusion-io's drives.
Iger - Wednesday, March 25, 2009 - link
This is the best review I've read in a very long time.Thank you very much!
BailoutBenny - Tuesday, March 24, 2009 - link
Great in depth article on flash based SSDs. I'm waiting for PRAM though.orclordrh - Tuesday, March 24, 2009 - link
Very illuminating article, very well written and researched. It made me glad that I didn't pull the trigger on an SSD for my I7 machine and regret not buying OCZ memory! I'm interested in adding an SSD as the scratch disk for Photoshop CS4 to use. I don't really launch applications very often, say once a week on the weekly reboot and keep 6-8 apps open at all times. I have 12GB of memory for that. The benchmarks were very interesting, but what sort of activity does Photoshop scratch usage create? Large files or random writes? What type of SSD would be most cost effective here?An SSD does sound better than a SSD!
semo - Wednesday, March 25, 2009 - link
wait for ddr3 to enter the mainstream and buy loads of memory.use a ramdisk for your adobe scratch area. much faster than ssd and no wear to worry about (not that you would worry that much with modern ssds anyway).
http://www.ghacks.net/2007/12/14/use-a-ramdisk-to-...">http://www.ghacks.net/2007/12/14/use-a-ramdisk-to-...
there is also a paid for and more feature rich ramdisk out there. can't remember the name
strikeback03 - Wednesday, March 25, 2009 - link
I'll have to check when I get home, but I believe the recommended size for the scratch disk is upwards of 10GB. So would need a motherboard that supports a LOT of RAM to give enough to main memory plus a scratch disk.strikeback03 - Wednesday, March 25, 2009 - link
I was wondering the same thing. I'd guess it would be a lot of writing/erasing, so an SSD might not be the best from a longevity standpoint, but if your system is hitting the scratch disk often then the speed might make it worthwhile.mikepers - Tuesday, March 24, 2009 - link
Anand,I wanted to compliment you on what I think was an excellent article. This is the type of thing I really have always liked from Anandtech. The detailed background, the technical reasons for the issues and then a thorough review of the current state of things.
I just finished upgrading my desktop. The only remaining item I wanted to replace was the hard disk. I had been thinking about getting a Velociraptor but instead I just ordered a 60GB Vertex from Newegg.
Thanks again for all the work.
Mike P.
ameatypie - Monday, March 23, 2009 - link
That sure was a lot to take in! Fantastic article though, it has really opened my eyes to the possibilities that Solid State Drives provide. Probably wont be buying one in the immediate future given the so-called depression and such things, but i will certainly keep up with SSD progress.Thanks again for your fantastic articles - im sure im not the only one who really appreciates them :)
coopchennick - Monday, March 23, 2009 - link
Hey Anand, I just finished reading through this whole article and I'm very impressed with the thoroughness and how informative it was.You just acquired a new regular reader.