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

  • speden - Wednesday, April 21, 2010 - link

    I still don't understand if the SandForce compression increases the available storage space. Is that discussed in the article somewhere? Is the user storage capacity 93.1 GB if you write uncompressable data, but much larger if you are writing normal data? If so that would effectively lower the cost per gigabyte quite a bit. Reply
  • Ryan Smith - Wednesday, April 21, 2010 - link

    It does not increase the storage capacity of the drive. The OS still sees xxGB worth of data as being on the drive even if it's been compressed by the controller, which means something takes up the same amount of reported space regardless of compressibility.

    The intention of SandForce's compression abilities was not to get more data on to the drive, it was to improve performance by reading/writing less data, and to reduce wear & tear on the NAND as a result of the former.

    If you want to squeeze more storage space out of your SSD, you would need to use transparent file system compression. This means the OS compresses things ahead of time and does smaller writes, but the cost is that the SF controller won't be able to compress much if anything, negating the benefits of having the controller do compression if this results in you putting more data on the drive.
  • arehaas - Thursday, April 22, 2010 - link

    The Sandforce drives report the same space available to the user, even if there is less data written to the drive. Does it mean that Sandforce drives should last longer because there are fewer actual writes to the NAND? One would reach the 10 million (or whatever) writes with Sandforce later than with other drives. Reply
  • Ryan Smith - Thursday, April 22, 2010 - link

    Exactly. Reply
  • MadMan007 - Wednesday, April 21, 2010 - link

    On a note somewhat related to another post here, I have a request. Could you guys please post final 'available to OS' capacity in *gibibytes*? (or if you must post gigabytes to go along with the marketers at the drive companies make it clear you are using GIGA and not GIBI) After I realized how much 'real available to OS' capacity can vary among drives which supposedly have the same capacity this would be very useful information...people need to know how much actual data they can fit on the drives and 'gibibytes available to the OS' is the best standard way to do that. Reply
  • vol7ron - Wednesday, April 21, 2010 - link

    Attach all corrections to this post.

    1st Paragraph: incredible -> incredibly
  • pattycake0147 - Thursday, April 22, 2010 - link

    On the second page, there is no link where the difference between the 1500 and the 1200 are referenced. Reply
  • Roland00 - Thursday, April 22, 2010 - link

    The problem with logarithmic scales is your brain interprets the data linerally instead of exponentially unless you force yourself not too. Reply
  • Per Hansson - Thursday, April 22, 2010 - link

    I agree
    Just as an idea you could have the option to click the graph and get a bigger version, I guess it would be something like 600x3000 in size but would give another angle at the data
    Because for 90% of your users I think a logramithic scale is very hard to comprehend :)
  • Impulses - Thursday, April 22, 2010 - link

    Not sure if this is the best place to post this but as I just remembered to do so, here goes... I have no issues whatsoever with your site re-design on my desktop, it's clean, it's pretty, looks fine to me.

    HOWEVER, it's pretty irritating on my netbook and on my phone... On the netbook the top edge of the page simply takes up too much space and leads to more scrolling than necessary on every single page. I'm talking about the banner ad, followed by the HUGE Anandtech logo (it's bigger than before isn't it), flanked by site navigation links, and followed by several more large bars for all the product categories. Even the font's big on those things... I don't get it, seems to take more space than necessary.

    Those tabs or w/e on the previous design weren't as clean looking, but they were certainly more compact. At 1024x600 I can barely see the title of the article I'm on when I'm scrolled all the way up (or not at all if I've enlarged text size a notch or two). It's not really that big a deal, but it just seems like there's a ton of wasted space around the site navigation links and the logo. /shrug

    Now on to the second issue, on my phone while using Opera Mini I'm experiencing some EXTREME slowdowns when navigating your page... This is a much bigger deal, it's basically useless... Can't even scroll properly. I've no idea what's wrong, since Opera Mini doesn't even load ads or anything like that, but it wasn't happening a week or two ago either so it's not because of the site re-design itself...

    It's something that has NEVER happened to me on any other site tho, they may load slow initially, but after it's open I've never had a site scrolls slowly or behave sluggishly within Opera Mini like Anandtech is doing right now... Could it be a rogue ad or something?

    I load the full-version of all pages on Opera Mini all the time w/o issue, but is there a mobile version of Anandtech that might be better suited for my phone/browser combination in the meantime?

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