The SSD Relapse: Understanding and Choosing the Best SSD
by Anand Lal Shimpi on August 30, 2009 12:00 AM EST- Posted in
- Storage
Used vs. New Performance: Revisited
Nearly all good SSDs perform le sweet when brand new. None of the blocks have any data in them, each write is performed at full speed, all is bueno. Over time, your drive gets written to, all blocks get occupied with data (both valid and invalid) and now every time you write to the SSD its controller has to do that painful read modify write and cleaning.
In the Anthology I simulated this worst used case by first filling the drive with data, deleting the partition, then installing the OS and running my benchmarks. This worked very well because it filled every single flash block with data. The OS installation and actual testing added a few sprinkles of randomness that helped make the scenario even more strenuous, which I liked.
The problem here is that if a drive properly supports TRIM, the act of formatting the drive will erase all of the wonderful used data I purposefully filled the drive with. My “used” case on a drive supporting TRIM will now just be like testing a drive in a brand new state.
To prove this point I provide you with an example of what happens when you take a drive supporting TRIM, fill it with data and then format the drive:
| SuperTalent UltraDrive GX 1711 | 4KB Random Write IOPS |
| Clean Drive | 13.1 MB/s |
| Used Drive | 6.93 MB/s |
| Used Drive After TRIM | 12.9 MB/s |
Oh look, performance doesn’t really change. The cleaning process takes longer now but other than that, the performance is the same.
So, I need a new way to test. It’s a shame because I’m particularly attached to the old way I tested, mostly because it provides a very stressful situation for the drives to deal with. After all, I don’t want to fool anyone into thinking a drive is faster than it is.
Once TRIM is enabled on all drives, the way I will test is by filling a drive after it’s been graced with an OS. I will fill it with both valid and invalid data, delete the invalid data and measure performance. This will measure how well the drive performs closer to capacity as well as how well it can TRIM data.
Unfortunately, no drives properly support TRIM yet. The beta Indilinx firmware with TRIM support works well, unless you put your system to sleep. Then there’s a chance you might lose your data. Woops. There’s also the problem with Intel’s Matrix Storage Manager not passing TRIM to your drives. All of this will get fixed before the end of the year, but it’s just a bit too early to get TRIM happy.
What we get today is the first stage of migrating the way we test. In order to simulate a real user environment I take a freshly secure erased drive, install Windows 7 x64 on it (no cloning, full install this time), then install drivers/apps, then fill the remaining space on the drive and delete it. This fills the drive with invalid data that the drive must keep track of and juggle, much like what you'd see by simply using your system.
I’m using the latest IMSM driver so TRIM doesn’t get passed to the drives; I’m such a jerk to these poor SSDs.
I’ll start look at both new and used performance on the coming pages. Once TRIM gets here in full force I’ll just start using it and we won't have to worry about looking at new vs. used performance.
The Test
| CPU | Intel Core i7 965 running at 3.2GHz (Turbo & EIST Disabled) |
| Motherboard: | Intel DX58SO (Intel X58) |
| Chipset: | Intel X58 |
| Chipset Drivers: | Intel 9.1.1.1015 + Intel IMSM 8.9 |
| Memory: | Qimonda DDR3-1066 4 x 1GB (7-7-7-20) |
| Video Card: | eVGA GeForce GTX 285 |
| Video Drivers: | NVIDIA ForceWare 190.38 64-bit |
| Desktop Resolution: | 1920 x 1200 |
| OS: | Windows 7 x64 |
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jengeek - Wednesday, September 2, 2009 - link
As of 09-02-09 from Toshiba Direct:80GB = $243
160GB = $473
http://www.toshibadirect.com/td/b2c/adet.to?poid=4...">http://www.toshibadirect.com/td/b2c/adet.to?poid=4...
http://www.toshibadirect.com/td/b2c/adet.to?poid=4...">http://www.toshibadirect.com/td/b2c/adet.to?poid=4...
gfody - Thursday, September 3, 2009 - link
nice thank you, ordered mine from herescrew Newegg! :D
jengeek - Wednesday, September 2, 2009 - link
Both are G2, in stock and ship the next dayBoth are retail box including the installation kit
Best price I've found
ARoyalF - Sunday, September 13, 2009 - link
Thank you posting that!I was going to wait out that awful price hike over at the egg.
You rock
ElderTech - Tuesday, September 1, 2009 - link
It's difficult to imagine the amount of time and effort that went into this article, Anand. Just the clean installs of Win7 took a fair amount of extra effort, let alone the other detailed diagrams and testing involved. From an old technology advocate over many years of working to keep pace with Moore's Law in a variety of research environments, your site provides the most satisfying learning experience of all. A sincere thank you!PS: As for the availability of the G2, it pops in and out of stock at a variety of online retailers, including Newegg, of course, as well as MWave. Both had it available for a short while at $249, Newegg on Friday and MWave today, Monday. However, it's out of stock presently as of midnight, EST 9-1-09 at both, with MWave still at $249 but Newegg going from there to $279 over the weekend and now at an amazing $499! OUCH. Sounds like supply and demand gouging if the price holds when they are next available! There is also some stock available in the distributor channel from small Intel Partners, as I confirmed by calling around the Chicago area. You might give this a try tomorrow. Good luck!
blyndy - Monday, August 31, 2009 - link
You really got performance anxiety because some high-profile people/sites liked your article and linked to it? It's hardly like it got printed in some prestigious science journal and the publishers are waiting on a follow-up.It was just the first time that SDD operation had been detailed in plain english from a reputable website.
Enough of this 'anthology' nonsense, I don't care if it's 1 page or 20, just tell me how some of the new SSDs perform (eg OCZ, Western Digital). You've already detailed how they work so now I want to know which ones do/will support TRIM and some details on the controller. Nothing to get anxious about.
Anand Lal Shimpi - Monday, August 31, 2009 - link
Indeed I did get performance anxiety after the last one, I even got it after the first X25-M. It's not so much the linkage, but the feedback from all of you guys. I received more positive feedback to the last SSD article than any one prior. More than anything I don't want to let you all down and I want to make sure I live up to everyone's expectations.As far as your interests go, all three manufacturers (Indilinx, Intel and Samsung) have confirmed support for TRIM. When? I'd say all three before December.
Take care,
Anand
cacca - Thursday, September 3, 2009 - link
Dear Anand i really thank you for your SSD articles, the improvements in this area seem tangible.Can I ask you to test Fusion-IO & ioXtreme, i am really curious to see how this other approach performs.
I know that isn't a perfect apple to apple comparison but at least we could compare the per $ performance.
Best regards
Ca
vol7ron - Monday, August 31, 2009 - link
Good article.I have a follow-up question regarding your size suggestion.
In more words you say, "get the size you need," but don't these drives perform that much better in a RAIDed system?
The cost per GB isn't that much more if you're looking at getting a 160GB Intel drive, to get the 2x 80GB instead.
SSDs are more reliable than HDs and you have the benefit of more RAM. 2x 32MB for an SSD in RAID0.
Curious to hear your thoughts,
vol7ron
StraightPipe - Tuesday, September 1, 2009 - link
Since RAID cards aren't going to support TRIM commands for a while, I'd stick with a large, single SSD.Anybody ahve any experience running these cards in RAID? I'd love to put some of these in my server, but i'm terrified of lossing data through the complexities of RAID combined with SSD.
I'd love to do a simple RAID1 setup, but it looks like i may be better of waiting too.
In the mean time, these look like a mean machine for an OS disk.