Random Read/Write Speed

This test reads/writes 4KB in a completely random pattern over an 8GB space of the drive to simulate the sort of random access 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.

I've had to run this test two different ways thanks to the way the newer controllers handle write alignment. Without a manually aligned partition, Windows XP executes writes on sector aligned boundaries while most modern OSes write with 4K alignment. Some controllers take this into account when mapping LBAs to page addresses, which generates additional overhead but makes for relatively similar performance regardless of OS/partition alignment. Other controllers skip the management overhead and just perform worse under Windows XP without partition alignment as file system writes are not automatically aligned with the SSD's internal pages.

First up is my traditional 4KB random write test, each write here is aligned to 512-byte sectors, similar to how Windows XP might write data to a drive:

4KB Random Write - MB/s

Here we see the first real impact of the SF-1200's final, shipping firmware. Random write performance drops down a bit, but not by a lot. However the SandForce controllers perform best when run in OSes that align across 4K boundaries:

4K Aligned - 4KB Random Write - MB/s

Here we see a dramatic drop. While the SF-1500 and SF-1200 (3.0.1) based SSDs manage over 160MB/s, the standard SF-1200 (3.0.5) can only push 44.2MB/s. That's still much faster than a HDD, but it ends up being slower than both a C300 and Intel's X25-M G2.

4KB Random Read - MB/s

The performance limitation only applies to small file random writes. Random read performance remains unchanged with version 3.0.5 of the SF-1200 firmware.

Sequential Read/Write Speed Random Data Performance


View All Comments

  • beginner99 - Friday, April 23, 2010 - link

    One thought:

    Wouldn't it be possible just tp use the vertex 2 "special" firmware for tis drive? I mean as far as i understood the controllers are 100% identical it is the firmware that makes the difference. Same should be true for any SF-1200 drive.
    But i'm not gonna try it out myself. ;)
  • Moonstarr - Sunday, May 9, 2010 - link

    Exactly what I was thinking. Take a look at the photos in the gallery and you'll see that the board revisions and controller are identical. Only the branding of the ram looks different. Reply
  • jordanl17 - Saturday, April 24, 2010 - link

    Does anyone use these SSDs in a server? Image a 7 drive raid-5 array ?!?!? it would be great. (I'm talking about for a Terminal Server 2008 64bit. all new hardware)

    I'd like to buy either an HP or IBM blade setup and use 2 of these drives in raid-1 in each blade.

    Does anyone know if this is possible? I know it wouldn't be as reliable as regular hard drive, but I'd keep a few on hand as backup.
  • charlielittle - Saturday, April 24, 2010 - link

    I'm using a 128gb NOVA in a Dell D820 with WinXP. I'd like to keep its great performance up to snuff without doing a full wipe. I was wondering, would it be possible to plug it in as an extra drive on my Win7 desktop and run some utility to force TRIM commands for any/all unused blocks on the drive? Does it have to be the boot drive for TRIM to be enabled by Win7?

  • iwodo - Sunday, April 25, 2010 - link

    While Sandforce was slower in Seq Read / Write with Random Data. Would the setting have any different on other non Sandforce SSD. Reply
  • pesos - Sunday, April 25, 2010 - link

    it would be awesome if a SAS 15k drive could be thrown into these SSD benchmarks going forward for those of us interested in doing enterprise comparisons! Reply
  • remmelt - Monday, April 26, 2010 - link

    The SSDnow V+ second generation doesn't perform all that well in the individual tests, but scores remarkably well in the overall performance graphs. Considering price per GB, this might be a great alternative.

    Can anyone explain the difference in the low scores on individual tasks and high scores in the overal benchmarks for this drive?
  • Squuiid - Monday, April 26, 2010 - link

    Anand, excellent review as always, thanks very much.

    Any updates on your Crucial drive? Are you now confident recommending the drive? Has the new one they sent you been reliable and has the performance degradation now been fixed?
    Sorry for the million questions.
  • brain42 - Wednesday, April 28, 2010 - link

    I notice that the latest drives have much higher random write performance than the random read performance, even though the typical scenario has more reads than writes.
    Could this be a symptom that the SSD industry is becoming so focused on random write, that the random read performance is forgotten? When all the reviewers focus solely on the random write performance, you can't really blame the industry for sacrificing performance in other areas.
  • fishak - Wednesday, April 28, 2010 - link

    remmelt, that is my question exactly. Why is the PC Mark score of the Intel G2 controller, so close to Sandforce, while the individual read and write scores of the Intel controller are so far behind?
    Per GB price of Intel is about $3.50, while Sandforce is about 4 bucks.

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