The SSD Relapse: Understanding and Choosing the Best SSD
by Anand Lal Shimpi on August 30, 2009 12:00 AM EST- Posted in
- Storage
Random Read/Write Speed
This test writes 4KB in a completely random pattern over an 8GB space of the drive to simulate the sort of random writes that you'd see on an OS drive (even this is more stressful than a normal desktop user would see). I perform three concurrent IOs and run the test for 3 minutes. The results reported are in average MB/s over the entire time:
As we established in previous articles, the disk operations that feel the slowest are the random small file reads and writes. Both of which are easily handled by an SSD. A good friend of mine and former AnandTech Editor, Matthew Witheiler, asked me if he'd notice the performance improvement. I showed him the chart above.
He asked again if he'd notice. I said, emphatically, yes.
Now this is super interesting. Intel's X25-M G1 drops from 40.8MB/s when new down to 26.3MB/s in a well used state. Unfortunately for the G1, it will never get TRIM and will spend more time in the lower performance state over the life of the drive. But look at what happens with the X25-M G2: it drops from 36.1MB/s to 35.8MB/s - virtually no performance is lost. In fact, the G2 is so fast here that it outperforms the super expensive X25-E. Granted you don't get the lifespan of the X25-E and the SLC drive should perform better on more strenuous random write tests, but this is a major improvement.
The explanation? It actually boils down to the amount of memory on the drive. The X25-M G1 had 16MB of 166MHz SDRAM on-board, the G2 upped it to 32MB of slower 133MHz DRAM. Remember that Intel doesn't keep any user data in DRAM, it's only used for the remapping, defragmenting and tracking of all of the data being written to the drive. More DRAM means that the drive can now track more data, which means that even in the heaviest of random-write workloads you could toss at it on a normal desktop you will not actually lose any performance with the drive in a used state. And this is the drive Intel has decided to grant TRIM to.
The G2 is good.
The Indilinx drives do lose performance here. They drop from roughly 13MB/s down to 7MB/s. We're still talking ~5x the speed of a VelociRaptor, so there's no cause for alarm. But it's clear that even Indilinx's SLC drive can't match Intel's random write performance. And from what I hear, Intel's performance is only going to get better.
This is what the X25-M price premium gets you.
Bahahaha, look at the hard drive scores here: 0.7MB/s and 0.3MB/s? That's freakin' terrible! And that's why your system feels so slow when you start it up, there are a ton of concurrent random reads and writes happening all over the place which your hard drive crunches through at roughly 0.5MB/s. Even the Samsung based OCZ Summit manages a significant performance advantage here.
The Indilinx drives all cluster around the 30 - 40MB/s mark for random read performance, nothing to be ashamed of. The Intel drives kick it up a notch and give you roughly 60MB/s of random read performance. It's a noticeable improvement. As our application launch tests will show however, loading a single app on either an Indilinx or Intel drive will take about the same amount of time. It's only in the heavy multitasking and "seat of the pants" feel that you'll have a chance at feeling a difference.
Facebook
Twitter
RSS
295 Comments
View All Comments
Anand Lal Shimpi - Monday, August 31, 2009 - link
Maybe I should compile these things into a book? :)Here are my answers about some stuff:
1) There's a spec for how hard drive makers report capacity. They define 1GB as 1 billion bytes. This is technically correct (base 10 SI prefix as you correctly pointed out). The HDDs also physically have this much storage on them, they are made up of sequentially numbered sectors that are easily counted in a decimal number system.
All other aspects of PC storage (e.g. cache, DRAM, NAND flash) however work in base 2 (like the rest of the PC). In these respects 1GB is defined as 1024^3 because we're dealing with a base 2 number system. There are reasons for this but it goes beyond the scope of what I'm posting :)
Intel adheres to the same spec that the HDD makers use. But the X25-M is made up of flash, which as I just mentioned is addressed in a base 2 number system. There's more flash than user space on the drive, it's used as spare area, woohoo. I think we're both on the same page here, just saying things differently :)
2) We'll see a 320GB drive, just not this year. I don't know that the demand is there especially given the weak economy.
Dreams do sometimes come true... ;)
3) Perhaps, but I don't like the idea of a drive doing anything but idling when it's supposed to be...idle. This does funny things to notebook battery life I'd think.
4) This is true. There's also another thing you can do with the jumper (and perhaps some additional software): flash any indilinx drive with any firmware regardless of vendor :)
5) I had to throw out a lot of data because of variations between runs. It ended up being a combination of immature drivers, immature benchmarks and some OS trickery. The setup I have now is very reliable and provides very repeatable results with very little variation. While I run everything three times, the runs are so close that you could technically do only one run per drive and still be fine.
6) I wouldn't count WD and Seagate out just yet. It may take them a while but they won't go quietly...
7) Samsung makes a ton of money from SSD sales to OEMs, they don't seem to care about the end user market as much. If end users start protesting Samsung drives however, things will change.
In my opinion? Once Apple falls, the rest will follow. If Apple will migrate to Intel (possible) or Indilinx (less likely), we'll see the same from the other OEMs and Samsung will be forced to change.
Or I could be too pessimistic and we'll see better performance from Samsung before then.
8) Agreed :)
I'll finish here too :)
Take care,
Anand
Reven - Monday, August 31, 2009 - link
Anand, dont listen to the guys like blyndy who diss on the anthologies, I love them. You can find a basic review anywhere, its the in-depth yet simple to understand stuff like these anthologies that make me visit Anandtech all the time.Keep it up, dude!
Anand Lal Shimpi - Monday, August 31, 2009 - link
Thank you :)EasterEEL - Monday, August 31, 2009 - link
I have a couple of questions regarding the Intel® SATA SSD Firmware Update Tool (2832KB) v1.3 8/24/2009.Does this firmware enable TRIM within the SSD to work with Windows 7?
If AHCI is enabled in the BIOS (but not RAID) does Windows 7 use it's own drivers with TRIM? Or does it load Intel’s Matrix Storage Manager driver which does not support TRIM as per the article note below?
"Unfortunately if you’re running an Intel controller in RAID mode (whether non-member RAID or not), Windows 7 loads Intel’s Matrix Storage Manager driver, which presently does not pass the TRIM command. Intel is working on a solution to this and I'd expect that it'll get fixed after the release of Intel's 34nm TRIM firmware in Q4 of this year."
Anand Lal Shimpi - Monday, August 31, 2009 - link
That update does not enable TRIM. The TRIM firmware is in testing now and it will be out sometime in Q4 of this year (October - December).If AHCI is enabled in the BIOS and you haven't loaded Intel's MSM drivers then it will use the Windows 7 driver and TRIM will be supported.
Take care,
Anand
uberowo - Monday, August 31, 2009 - link
I do have a question however. :DI am building a gaming pc, and I am buying ssd disk/s. Would I benefit from getting 2x80gb intel gen2s and using raid0? Or should I stick with a single 160gb?
Anand Lal Shimpi - Monday, August 31, 2009 - link
While I haven't tested 2 x 80GB drives in RAID-0, my feeling is that a single SSD is going to be better than two in RAID going forward. As of now I don't know that anyone's TRIM firmware is going to work if you've got two drives in RAID-0.The perceived performance gains in RAID-0 also aren't that great on SSDs from what I've seen.
Take care,
Anand
Ardax - Monday, August 31, 2009 - link
A naive guess would be that it depends on the workload. For lots of sequential transfers a RAID-0 should shine -- particularly on reads -- because you're spreading the transfers out over multiple SATA channels.Losing TRIM is a problem. Finding a controller than can handle the performance is entirely likely to be another.
uberowo - Monday, August 31, 2009 - link
Thanks a lot for taking the time to answer. Not to mention making this awesome site. :)Anand Lal Shimpi - Monday, August 31, 2009 - link
You guys take the time to read it and make some truly wonderful comments, it's the least I can do :)-A