The SSD Relapse: Understanding and Choosing the Best SSD
by Anand Lal Shimpi on August 30, 2009 12:00 AM EST- Posted in
- Storage
Individual Application Performance
PCMark Vantage does a great job of summarizing system performance, but I thought I'd pick a couple of applications to showcase real world strengths/weaknesses of these drives.
The first test is our Photoshop CS4 benchmark by the Retouch Artists. I made one small change to the way this test is run however. Normally I set the number of history states in Photoshop to 1, this significantly reduces the impact of the HDD/SSD on the test and makes it a better measure of CPU/memory speed. Since this is an SSD article, I've left the setting at its default value of 20. The numbers are now a lot lower and the performance a lot more disk bound.
I didn't run all of the drives through this test, just one from each major controller. The results speak for themselves. The Indilinx drives are actually the fastest MLC drives here. Even the Samsung is faster than the Intel drives in this test. Why? Sequential write speed. Even the VelociRaptor has a higher sequential write speed than the X25-M. So while sequential write speed isn't the most important metric to look at when evaluating an SSD, there are real world situations where it does matter.
Intel's performance here is just embarassing. Sequential write speed is something Intel needs to take more seriously in the future. Throw in any amount of random read/write operations alongside your Photoshop usage and the Intel drives would redeem themselves, but this is a very realistic snapshot of their achilles' heel.
Many of you have been asking for compiler benchmarks so I did just that. I grabbed the latest source for Pidgin (a popular IM application) and followed the developer's instructions on building it in Windows:
Nada. I thought perhaps it wasn't stressful enough so I tried building two instances in parallel:
And...nothing. It seems that building Pidgin is more CPU than IO bound, or at least its IO access isn't random enough to really benefit from an SSD. I'll keep experimenting with other compiler tests but this one appears to be a bust for SSD/HDD performance testing.
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Anand Lal Shimpi - Monday, August 31, 2009 - link
The tables the drive needs to operate are also stored in a small amount of flash on the drive. The start of the circular logic happens in firmware which points to the initial flash locations, which then tells the controller how to map LBAs to flash pages.Take care,
Anand
Bakkone - Monday, August 31, 2009 - link
Any gossip about the new SATA?Zaitsev - Monday, August 31, 2009 - link
Thanks for the great article, Anand! It's been quite entertaining thus far.cosmotic - Monday, August 31, 2009 - link
The page about sizes (GB, GiB, spare areas, etc) is very confusing. It sounds very much like you are confusing the 'missing' space when converting from GB to GiB with the space the drive is using for its spare area.Is it the case that the drive has 80GiB internally, uses 5.5GiB for spare, and reports it's size as 80GB to the OS leaving the OS to say 74.5GiB as usable?
Anand Lal Shimpi - Monday, August 31, 2009 - link
I tried to keep it simply by not introducing the Gibibyte but I see that I failed there :)You are correct, the drive has 80GiB internally, uses 5.5GiB for spare and reports that it has 156,301,488 sectors (or 74.5GiB) of user addressable space.
Take care,
Anand
sprockkets - Tuesday, September 1, 2009 - link
Weird. So what you are saying is, the drive has 80Gib capacity, but then reports it has 80GB to the OS, advertised as having an 80GB capacity, which the OS then says the capacity is 74.5GiB?sprockkets - Tuesday, September 1, 2009 - link
As a quick followup, this whole SI vs binary thing needs to be clarified using the proper terms, as people like Microsoft and others have been saying GB when it really is GiB (or was the GiB term invented later?)For those who want a quick way to convert:
http://converter.50webs.com">http://converter.50webs.com
ilkhan - Monday, August 31, 2009 - link
so they are artifically bringing the capacity down, because the drive has the full advertised capacity and is getting the "normal" real capacity. :argh:Vozer - Monday, August 31, 2009 - link
I tried looking for the answer, but haven't found it anywhere so here it is: There are 10 flash memory blocks on both Intel 160GB and 80GB X25-M G2, right? (and 20 blocks with the G1).So, is the 80GB version actually a 160GB with some bad blocks or do they actually produce two different kind of flash memory block to use on their drives?
Anand Lal Shimpi - Monday, August 31, 2009 - link
While I haven't cracked open the 80GB G2 I have here, I don't believe the drives are binned for capacity. The 80GB model should have 10 x 8GB NAND flash devices on it, while the 160GB model should have 10 x 16GB NAND flash devices.Take care,
Ananad