Random Read/Write Performance

Arguably much more important to any PC user than sequential read/write performance is random access performance. It's not often that you're writing large files sequentially to your disk, but you do encounter tons of small file reads/writes as you use your PC.

To measure random read/write performance I created an iometer script that peppered the drive with random requests, with an IO queue depth of 3 (to add some multitasking spice to the test). The write test was performed over an 8GB range on the drive, while the read test was performed across the whole drive. I ran the test for 3 minutes.

The three hard drives all posted scores below 1MB/s and thus aren't visible on our graph above. This is where SSDs shine and no hard drive, regardless of how many you RAID together, can come close.

The two Intel drives top the charts and maintain a huge lead. The OCZ Vertex actually beats out the more expensive (and unreleased) Summit drive with a respectable 32MB/s transfer rate here. Note that the Vertex is also faster than last year's Samsung SLC drive that everyone was selling for $1000. Even the JMicron drives do just fine here.

If we look at latency instead of transfer rate it helps put things in perspective:

Read latencies for hard drives have always been measured in several ms, but every single SSD here manages to complete random reads in less than 1ms under load.

Random write speed is where we can thin the SSD flock:

Only the Intel drives and to an extent, the OCZ Vertex, post numbers visible on this scale. Let's go to a table to see everything in greater detail:

4KB Random Write Speed  
Intel X25-E 31.7 MB/s
Intel X25-M 23.1 MB/s
JMicron JMF602B MLC 0.02 MB/s
JMicron JMF602Bx2 MLC 0.03 MB/s
OCZ Summit 0.77 MB/s
OCZ Vertex 2.41 MB/s
Samsung SLC 0.53 MB/s
Seagate Momentus 5400.6 0.81 MB/s
Western Digital Caviar SE16 1.26 MB/s
Western Digital VelociRaptor 1.63 MB/s

Every single drive other than the Intel X25-E, X25-M and OCZ's Vertex is slower than the 2.5" Seagate Momentus 5400.6 hard drive in this test. The Vertex, thanks to OCZ's tweaks, is now 48% faster than the VelociRaptor.

The Intel drives are of course architected for the type of performance needed on a desktop/notebook and thus they deliver very high random write performance.

Random write performance is merely one corner of the performance world. A drive needs good sequential read, sequential write, random read and random write performance. The fatal mistake is that most vendors ignore random write performance and simply try to post the best sequential read/write speeds; doing so simply produces a drive that's undesirable.

While the Vertex is slower than Intel's X25-M, it's also about half the price per GB. And note that the Vertex is still 48% faster than the VelociRaptor here, and multiple times faster in the other tests.

Sequential Read/Write Performance SYSMark 2007
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  • SSDMaster - Friday, March 20, 2009 - link

    Yes, it does.
    I have a Core series 60GB OCZ drive. I bought it right before Newegg increased the price on the drives. The stuttering was horrible, and worthless even as a secondary drive if it was formatted with XP. Also, after using Diskpart and aligning the drive I could not install XP on the drive and have it bootable.. Which sucked.

    But there's ways around that, and guess what, I have a stutter free flash drive for cheap that gets very good performance numbers, and boots Server 2008 in under 10 seconds.
    Reply
  • bsoft16384 - Thursday, March 19, 2009 - link

    OCZ's product works fine. You may not like the performance, but it's certainly not unusable.

    The $65 I paid for my 30GiB OCZ "Solid" SSD is about what you'd pay for a USB flash drive. The disk I have has a USB interface, which is very convenient, plus it's plenty fast enough for my EEE PC.

    I'm glad that Anand has done these reviews. People need to understand what they're getting into when they by a JMicron SSD. If you don't expect much, you won't be disappointed.

    Arguably for a normal notebook/desktop you should buy a normal hard drive if your budget is under $100. But the JMicron SSDs do a good job in netbooks (which, again, aren't too fast to begin with) at a very low price.

    I have aligned my partitions and disabled swap on my Windows 7 install (on my EEE). I also have 2GB of memory in my EEE. I haven't done any fancy tweaking on the OS.

    Compared with the EEE 900A that I had briefly (PCIe SSD), my EEE 900HA is dramatically faster. You can't run XP or Vista on PCIe SSDs unless you have a lot of patience. You *can* run it on a JMicron SSD.

    I honestly don't notice any stuttering. I don't run antivirus and I don't multitask much on this machine. If I demanded from my EEE what I demand from my desktop (Q9300 + 8GB + WD6400AAKS), I know that the SSD would choke up. But I'm not going to do that on a 1.6GHz single-core Atom anyway.

    So, yeah, OK. I guess I think that trashing JMicron SSDs is a little like trashing USB flash drives for being slow. Paying $300 for a UFD would be stupid, as is paying $300 for a JMicron SSD. But in the sub-$100 category, you don't expect much.

    When better SSDs drop below $100, maybe I'll upgrade. Until then, I'm enjoying 5 hours of battery life on my 900HA.
    Reply
  • tomoyo - Thursday, March 19, 2009 - link

    Well I think it's unusable for my needs if I'm running it as an operating system drive. I place a giant important on the latency of the drive at that point and it certainly includes random writes. Which is why I would never ever buy an ssd that's majorly below the Intel write performance. It's not worth the price premium or loss of storage size compared to the standard hard drive. Reply
  • Bikerskummm - Thursday, March 19, 2009 - link

    Fantastic article Anand!

    Just a few thoughts:

    I have had some trouble replicating some of the Samsung SLC results...

    Despite filling the drive up and emulating a well used drive as described in the article I cannot get my Sammy drive's performance to degrade as much as you managed to especially regarding random write performance...

    Now my system used for testing is a socket 775 (qx9650) and I was testing on ICH9R and WINXP (SP3) but still I would expect to see similar figures ...

    I do not have an X58 system to test on at the moment but I would be very interested if The Sammy SLC drives were shown to degrade faster / perform worse with a X58 / ICH10R / Vista x64 (SP1?) setup...
    Reply
  • siberx - Thursday, March 19, 2009 - link

    This is, very likely, the best article I have ever read, period. Online, in magazines, about any subject... this was an absolutely fantastic read. Suddenly, all smoke surrounding SSDs has cleared and the truth shines through in editorial brilliance. It's great to see that at least some computer news sites out there can still cut through the crap and get to the heart of the issue. My already high opinion of AnandTech has risen even further.

    Thank you for taking the immense time it must have taken to compile and assemble all this information - this article is now a must-read for *anybody* considering purchasing an SSD, and it's just about all the background you could need in one place.

    In addition to all the extremely useful general SSD information contained within, the detailing of the issues with the JMicron controllers as well as OCZ's efforts to address the concerns to produce the best product possible (despite the reduced marketability to the uninformed) is reassuring and comforting in a world where tech companies seem more concerned with how much they can deceive their customers instead of producing quality products.

    In short, the article is a win on all fronts, thank you greatly for posting it. When I purchase my first SSD (which I'm considering doing reasonably soon) this article, its information and suggestions, and OCZs actions to resolve the issues with its drives will definitely be at the forefront of my mind.
    Reply
  • jkua - Thursday, March 19, 2009 - link

    I have to say, I really appreciate the effort and throughness with which you have covered the state of the SSD market today. As an engineer and scientist, I applaud your methods in tracking down and reporting the major issues with SSDs. As a consumer, I really appreciate the timeliness of this article as I was just thinking of putting an SSD in a netbook for a robotics application where mechanical drives are not ideal.

    Cheers!
    Reply
  • jkua - Thursday, March 19, 2009 - link

    That said, one thing I would have like to have seen is some numbers on power consumption for these drives compared to average mechanical desktop and laptop drives. Reply
  • aamsel - Thursday, March 19, 2009 - link

    Anyone have a link to the Intel HDD ERASE program that Anand referred to? Reply
  • HolyFire - Thursday, March 19, 2009 - link

    http://www.ultimatebootcd.com/download.html">http://www.ultimatebootcd.com/download.html (includes HDD erase 3.1)

    http://cmrr.ucsd.edu/people/Hughes/SecureErase.sht...">http://cmrr.ucsd.edu/people/Hughes/SecureErase.sht... (version 4.0)
    Reply
  • AnnonymousCoward - Thursday, March 19, 2009 - link

    AWESOME ARTICLE.

    The huge difference in read/write flash performance looks a lot like this article: http://www.anandtech.com/memory/showdoc.aspx?i=257...">http://www.anandtech.com/memory/showdoc.aspx?i=257...
    Reply

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