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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zdzichu - Sunday, March 22, 2009 - link
Very nice and thorough article. I only lack more current status of TRIM command support in current operating systems. For example, Linux supports it since last year:http://kernelnewbies.org/Linux_2_6_28#head-a1a9591...">http://kernelnewbies.org/Linux_2_6_28#h...a9591f48...
Sinned - Sunday, March 22, 2009 - link
Outstanding article that really helped me understand SSD drives. I wonder how much of an impact the new SATA III standard will have on SSD drives? I believe we are still at the beginning stage for SSD drives and your article shows that much more work needs to be done. My respect for OCZ and how they responded in a positive and productive way should be a model for the rest of the SSD makers. Thank you again for such a concise article.Respectfully,
Sinned
529th - Sunday, March 22, 2009 - link
The first thing I thought of was Democracy. Don't know why. Maybe it was because a company listened to our common goal of performance. Thank you OCZ for listening, I'm sure it will pay off!!!araczynski - Saturday, March 21, 2009 - link
very nice read. the 4/512 issue seems a rather stupid design decision, or perhaps more likely a stupid problem to find this 4/512 solution as 'acceptable'.although a great marketing choice, built in automatic life expectancy reduction.
sounds like the manufacturers want the hard drives to become a disposable medium like styrofoam cups.
perhaps when they narrow the disparity down to 4/16, i might consider buying an ssd. that, or when they beat the 'old school' physical platters in price.
until then, get back to the drawing board and stop crapping out these half arsed 'should be good enough' solutions.
IntelUser2000 - Sunday, March 22, 2009 - link
araczynski: The 4/512 isn't done by accident. It's done to lower prices. The flash technology used in SSDs are meant to replace platter HDDs in the future. There's no way of doing that without cost reductions like these. Even with that the SSDs still cost several times more per storage space.araczynski - Tuesday, March 24, 2009 - link
i understand that, but i don't remember original hard drives being released and being slower than the floppy drives they were replacing.this is part of the 'release beta' products mentality and make the consumer pay for further development.
the 5.25" floppy was better than the huge floppy in all respects when it was released. the 3.5" floppy was better than the 5.25" floppy when it was released. the usb flash drives were better than the 3.5" floppies when they were released.
i just hate the way this is being played out at the consumer's expense.
hellcats - Saturday, March 21, 2009 - link
Anand,What a great article. I usually have to skip forwards when things bog down, but they never did with this long, but very informative article. Your focus on what matters to users is why I always check anandtech first thing every morning.
juraj - Saturday, March 21, 2009 - link
I'm curious what capacity is the OCZ Vertex drive reviewed. Is it an 120 / 250g drive or supposedly slower 30 / 60g one?Symbolics - Friday, March 20, 2009 - link
The method for generating "used" drives is flawed. For creating a true used drive, the spare blocks must be filled as well. Since this was not done, the results are biased towards the Intel drives with their generous amount of spare blocks that were *not* exhausted when producing the used state. An additional bias is introduced by the reduction of the IOmeter write test to 8 GB only. Perhaps there are enough spare blocks on the Intel drives so that these 8 GB can be written to "fresh" blocks without the need for (time-consuming) erase operations.Apart from these concerns, I enjoyed reading the article.
unknownError - Saturday, March 21, 2009 - link
I also just created an account to post, very nice article!Lots of good well thought out information, I'm so tired of synthetic benchmarks glad someone goes through the trouble to bench these things right (and appears to have the education to really understand them). Whats with the grammar police though? geez...