The SSD Relapse: Understanding and Choosing the Best SSD
by Anand Lal Shimpi on August 30, 2009 12:00 AM EST- Posted in
- Storage
One Tough Act to Follow
What have I gotten myself into? The SSD Anthology I wrote back in March was read over 2 million times. Microsoft linked it, Wikipedia linked it, my esteemed colleagues in the press linked it, Linus freakin Torvalds linked it.
The Anthology took me six months to piece together; I wrote and re-wrote parts of that article more times than I'd care to admit. And today I'm charged with the task of producing its successor. I can't do it.
The article that started all of this was the Intel X25-M review. Intel gave me gold with that drive; the article wrote itself, the X25-M was awesome, everything else in the market was crap.
Intel's X25-M SSDs: The drives that started a revolution
The Anthology all began with a spark: the SSD performance degradation issue. It took a while to put together, but the concept and the article were handed to me on a silver platter: just use an SSD for a while and you’ll spot the issue. I just had to do the testing and writing.
OCZ's Vertex: The first Indilinx drive I reviewed, the drive that gave us hope there might be another.
But today, as I write this, the words just aren't coming to me. The material is all there, but it just seems so mature and at the same time, so clouded and so done. We've found the undiscovered country, we've left no stone unturned, everyone knows how these things work - now SSD reviews join the rest as a bunch of graphs and analysis, hopefully with witty commentary in between.
It's a daunting, no, deflating task to write what I view as the third part in this trilogy of articles. JMicron is all but gone from the market for now, Indilinx came and improved (a lot) and TRIM is nearly upon us. Plus, we all know how trilogies turn out. Here's hoping that this one doesn't have Ewoks in it.
What Goes Around, Comes Around
No we're not going back to the stuttering crap that shipped for months before Intel released their X25-M last year, but we are going back in the way we have to look at SSD performance.
In my X25-M review the focus was on why the mainstream drives at the time stuttered and why the X25-M didn't. Performance degradation over time didn't matter because all of the SSDs on the market were slow out of the box; and as I later showed, the pre-Intel MLC SSDs didn’t perform worse over time, they sucked all of the time.
Samsung and Indilinx emerged with high performance, non-stuttering alternatives, and then we once again had to thin the herd. Simply not stuttering wasn't enough, a good SSD had to maintain a reasonable amount of performance over the life of the drive.
The falling performance was actually a side effect of the way NAND flash works. You write in pages (4KB) but you can only erase in blocks (128 pages or 512KB); thus SSDs don't erase data when you delete it, only when they run out of space to write internally. When that time comes, you run into a nasty situation called the read-modify-write. Here, even to just write 4KB, the controller must read an entire block (512KB), update the single page, and write the entire block back out. Instead of writing 4KB, the controller has to actually write 512KB - a much slower operation.
I simulated this worst case scenario performance by writing to every single page on the SSDs I tested before running any tests. The performance degradation ranged from negligible to significant:
| PCMark Vantage HDD Score | New | "Used" |
| Corsair P256 (Samsung MLC) | 26607 | 18786 |
| OCZ Vertex Turbo (Indilinx MLC) | 26157 | 25035 |
So that's how I approached today's article. Filling the latest generations of Indilinx, Intel and Samsung drives before testing them. But, my friends, things have changed.
The table below shows the performance of the same drives showcased above, but after running the TRIM instruction (or a close equivalent) against their contents:
| PCMark Vantage HDD Score | New | "Used" | After TRIM/Idle GC | % of New Perf |
| Corsair P256 (Samsung MLC) | 26607 | 18786 | 24317 | 91% |
| OCZ Vertex Turbo (Indilinx MLC) | 26157 | 25035 | 26038 | 99.5% |
Oh boy. I need a new way to test.
Facebook
Twitter
RSS
295 Comments
View All Comments
sunbear - Monday, August 31, 2009 - link
Even though most laptops are now SATA-300 compatible, the majority are not able to actually exceed SATA-150 transfer speeds according to some people who have tried. I would imagine that sequential read/write performance would be important for swap but the SATA-150 will be the limiting factor for any of the SSD's mentioned in Anand's article in this case.Here's the situation with Thinkpads:
http://blogs.technet.com/keithcombs/archive/2008/1...">http://blogs.technet.com/keithcombs/arc...vo-think...
The new MacBookPro is also limited to SATA-150.
smartins - Tuesday, September 1, 2009 - link
Actually, The ThinkPad T500/T400/W500 are fully SATA-300 compatible, it's only the drives that ship with the machines that are SATA-150 capped.I have a Corsair P64 on my T500 and get an average of 180MB/read which is consistent with all the reviews of this drive.
mczak - Monday, August 31, 2009 - link
article says you shouldn't expect it soon, but I don't think so. Several dealers already list it, though not exactly in stock (http://ht4u.net/preisvergleich/a444071.html)">http://ht4u.net/preisvergleich/a444071.html). Price tag, to say it nicely, is a bit steep though.Seramics - Monday, August 31, 2009 - link
Another great articles from Anandtech. Kudos guys at AT, ur my no. 1 hardware site! Anyway, its really great that we have a really viable competitor to Intel- Indilinx. They really deserve the praise. Now we can buy a non Intel SSD and have no nonsensical stuttering issue! Overall, Intel is still leader but its completely nonsensical how bad their sequential write speed is! I mean, its even slower than a mechanical hard disk! Thats juz not acceptable given the gap in performance is so large and Intel SSD's actually can suffer a significantly worst performance in real world when sequential write speed performance matters. Intel, fix your seq write speed nonsence please!Seramics - Monday, August 31, 2009 - link
Sorry for double post. Its unintentional and i duno how to delete the 2nd post.Seramics - Monday, August 31, 2009 - link
Another great articles from Anandtech. Kudos guys at AT, ur my no. 1 hardware site! Anyway, its really great that we have a really viable competitor to Intel- Indilinx. They really deserve the praise. Now we can buy a non Intel SSD and have no nonsensical stuttering issue! Overall, Intel is still leader but its completely nonsensical how bad their sequential write speed is! I mean, its even slower than a mechanical hard disk! Thats juz not acceptable given the gap in performance is so large and Intel SSD's actually can suffer a significantly worst performance in real world when sequential write speed performance matters. Intel, fix your seq write speed nonsence please!Shadowmaster625 - Monday, August 31, 2009 - link
Subtle. Very subtle. Good article though.3 questions:
1. Is there any way to read the individual page history off the SSD device so I can construct a WinDirStat style graphical representation of the remaining expected life of the flash? Or better yet is there already a program that does this?
2. Suppose I had a 2 gigabyte movie file on my 60gb vertex drive. And suppose I had 40GB of free space. If I were to make 20 copies of that movie file, then delete them all, would that be the same as running Wiper?
3. Any guesses as to which of these drives will perform best when we make the move to SATA-III?
4. (Bonus) What is stopping Intel from buying Indilinx (and pulling their plug)? (Or just pulling their plug without buying them...)
SRSpod - Thursday, September 3, 2009 - link
3. These drives will perform just as they do now when connected to a 6 GBps SATA controller. In order to communicate at the higher speed, both the drive and the controller need to support it. So you'll need new 6 GBps drives to connect to your 6 GBps controller before you'll see any benefit from the new interface.heulenwolf - Monday, August 31, 2009 - link
Yeah, once the technology matures a little more and drives become more commoditized, I'd like to see more features in terms of feedback on drive life, reliability, etc. When I got my refurb Samsung drives from Dell, for example, they could have been on the verge of dying or they could have been almost new. There's no telling. The controller could know exactly where the drive stands, however. Some kind of controller-tracked indication of drive life left would be a feature that might distinguish comparable drives from one another in a crowded marketplace.While they're at it, a tool to allow adjusting of values such as the amount of space not reported to the OS with output in terms of write amplification and predicted drive life would be really nifty.
Sure, its over the top, but we can always hope.
nemitech - Monday, August 31, 2009 - link
I picked up an Agility 120 Gb for $234 last week from ebay ($270 list price - - 6% bing cashback - $20 pay pal discount). I am sure there will be similar deals around black Friday. $2 per Gb is possible for a good SSD.