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 |
Facebook
Twitter
RSS
295 Comments
View All Comments
sotoa - Friday, September 4, 2009 - link
Another great article. You making me drool over these SSD's!I can't wait till Win7 comes to my door so I can finally get an SSD for my laptop.
Hopefully prices will drop some more by then and Trim firmware will be available.
lordmetroid - Thursday, September 3, 2009 - link
I use them both because they are damn good and explanatory suffixes. It is 2009, soon 2010 I think we can at least get the suffixes correct, if someone doesn't know what they mean, wikipedia has answers.AnnonymousCoward - Saturday, September 5, 2009 - link
As someone who's particular about using SI and being correct, I think it's better to stick to GB for the sake of simplicity and consistency. The tiny inaccuracy is almost always irrelevant, and as long as all storage products advertise in GB, it wouldn't make sense to speak in terms of GiB.Touche - Thursday, September 3, 2009 - link
Both articles emphasize Intel's performance lead, but, looking at real world tests, the difference between it and Vertex is really small. Not hardly enough to justify the price difference. I feel like the articles are giving an impression that Intel is in a league of its own when in fact it's only marginally faster.smjohns - Tuesday, September 8, 2009 - link
This is where I struggle. It is all very well quoting lots of stats about all these drives but what I really want to know is if I went for Intel over the OCZ Vertex (non-turbo) where would I really notice the difference in performance on a laptop?Would it be slower start up / shut down?
Slower application response times?
Speed at opening large zipped files?
Copying / processing large video files?
If the difference is that slim then I guess it is down to just a personal preference....
morrie - Thursday, September 3, 2009 - link
I've made it a habit of securely deleting files by using "shred" like this: shred -fuvz, and accepting the default number of passes, 25. Looks like this security practice is now out, as the "wear" on the drive would be at least 25x faster, bringing the stated life cycles closer to having an impact on drive longevity. So what's the alternative solution for securely deleting a file? Got to "delete" and forget about security? Or "shred" with a lower number of passes, say 7 or 10, and be sure to purchase a non-Intel drive with the ten year warranty and hope that the company is still in business, and in the hard drive business, should you need warranty service in the outer years...Rasterman - Wednesday, September 16, 2009 - link
watching too much CSI, there is an article somewhere i read by a data repair tech who works in one of the multi-million dollar data recovery labs, basically he said writing over it once is all you should do and even that is overkill 99% of the time. theoretically it is possible to even recover that _sometimes_, but the expense required is so high that unless you are committing a billion dollar fraud or are the secretary to osama bin laden no one will ever try to recover such data. chances are if you are in such circles you can afford a new drive 25x more often. and if you have such information or knowledge wouldn't be far easier and cheaper to simply beat it out of you than trying to recover a deleted drive?iamezza - Friday, September 4, 2009 - link
1 pass should be sufficient for most purposes. Unless you happen to be working on some _extremely_ sensitive/important data.derkurt - Thursday, September 3, 2009 - link
I may be wrong on this, but I'd assume that once TRIM is enabled, a file is securely deleted if it has been deleted on the filesystem level. However, it might depend on the firmware when exactly the drive is going to actually delete the flash blocks which are marked as deletable by TRIM. For performance reasons the drive should do that as soon as possible after a TRIM command, but also preferably at a time when there is not much "action" going on - after all, the whole point of TRIM is to change the time of block erasing flash cells to a point where the drive is idle.
morrie - Thursday, September 3, 2009 - link
That's on a Linux system btwAs to aligning drives...how about an update to the article on what needs to be done/ensured, if anything, for using the drives with a Linux OS?