Random Read/Write Speed

The four corners of SSD performance are as follows: random read, random write, sequential read and sequential write speed. Random accesses are generally small in size, while sequential accesses tend to be larger and thus we have the four Iometer tests we use in all of our reviews.

Our first test 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. We use both standard pseudo randomly generated data for each write as well as fully random data to show you both the maximum and minimum performance offered by SandForce based drives in these tests. The average performance of SF drives will likely be somewhere in between the two values for each drive you see in the graphs. For an understanding of why this matters, read our original SandForce article.

Iometer - 4KB Random Write, 8GB LBA Space, QD=3

Random write performance looks extremely good on the Agility 3, even with incompressible data (at least at low queue depths). Like the original Agility, it's impossible to tell the performance difference between it and the Vertex 3 here.

Many of you have asked for random write performance at higher queue depths. What I have below is our 4KB random write test performed at a queue depth of 32 instead of 3. While the vast majority of desktop usage models experience queue depths of 0 - 5, higher depths are possible in heavy I/O (and multi-user) workloads:

Iometer - 4KB Random Write, 8GB LBA Space, QD=32

Even as we ramp up queue depth in Iometer, the Agility 3 sticks to the performance of the Vertex 3. It's only with incompressible data that we see the first hint of a performance deficit, but even that isn't much.

Iometer - 4KB Random Read, QD=3

Random read performance is unfortunately limited to 120GB Vertex 3 levels. It's unclear to me whether this is an asynchronous NAND issue or an artificial firmware cap.

Sequential Read/Write Speed

To measure sequential performance I ran a 1 minute long 128KB sequential test over the entire span of the drive at a queue depth of 1. The results reported are in average MB/s over the entire test length.

Iometer - 128KB Sequential Read

Sequential read performance is lower than the Vertex 3. The 240GB Agility 3 performs more like a 120GB Vertex 2 than its 240GB sibling.

Iometer - 128KB Sequential Write

Sequential write speed is competitive but generally not better than the Vertex 3.

Introduction AnandTech Storage Bench 2011 - Heavy Workload


View All Comments

  • Nicolas Pillot - Friday, May 27, 2011 - link

    Seeing Vertex 2 120G and Agility 3 120G at the same price, which one should i buy ?
    BTW : no sata 3 motherboard at the moment, so choice shouldn't be based on it.
  • DanaG - Wednesday, June 01, 2011 - link

    I sure hope the Agility/Vertex 3 drives are more reliable than the Vertex 2 is. I had one fail two weeks ago, and then the replacement I got last Wednesday failed on Saturday. I believe it happened when we had a momentary interruption in power. The laptop and secondary-bay HDD are fine, and the drive kept working until I shut it down; once I did so, the drive became totally unresponsive.

    The drives also can't handle ATA Password properly:

    From the forums and Newegg's reviews, it looks like plenty of other people have similar issues. For comparison, I've had zero issues with my old Indilinx drive. I like the performance of the Vertex 2, but I don't feel confident in the reliability of any Sandforce drives now.

    Anand, can you please talk to the OCZ people about these sorts of things?
  • cactusjuggler - Wednesday, June 01, 2011 - link

    Firstly, I really appreciate AT's in depth reviews. That said, I absolutely agree with DanaG, and I don't see reviews addressing the reliability of these drives--particularly SandForce ones.

    I'm pricing out two new computers at the moment, and have been surveying the SSD landscape. If I made a buying decision purely on this review and others that focus on performance I'd already have ordered a Vertex 2 or the like, but after reading enough about failed drives, there's no way I'm buying anything with a SandForce controller for a good long time.

    Based on the sheer number of anecdotes I'm seeing I find it odd that reviews aren't even mentioning the issue of reliability. 6 out of 10 of the most recent comments on Newegg for the OCZ Agility 2 are complaining about outright failure (in some cases replaced drives also failed), or major problems using the drive.

    That sort of track record is embarrassing in a retail product, and really makes me wary about the reliability of the technology overall. Compounded with the apparent fact that data on a bricked drive is irretrievable in many (the majority?) of cases, and you really have to think twice about using one.

    Given all this it's kind of amazing, and downright laughable, that some of these drives are supposedly targeted at enterprise level customers.
  • rajeanand - Wednesday, June 01, 2011 - link

    For all those looking for a Corsair Force 3 review, the first on is now online: http://www.kitguru.net/components/ssd-drives/zardo...

    Seems performance is very similar to the Agility3 reviewed in this article, although the Force 3 reviewed in the article is a 120GB
  • curiousincal - Friday, December 02, 2011 - link

    Can tell me the preconditioning for the random read test and the preconditioning for the random write test used here?

  • johan008 - Thursday, January 26, 2012 - link

    Mine died after 4 months. OCZ used "unauthorized reseller or warranty not transferable" to stop all the claims. I was problem ticket no: 240 526 and it keep rising fast. See OCZ discussion forum before you buy as these SSD from OCZ are still very unstable. Reply
  • jdtwoseven - Wednesday, August 01, 2012 - link

    I've had three OCZ SSD products, including one of these Agility 3 240 gb SSDs, and I've ended up having to RMA each one of them. That is a terrible record of reliability for the drives. The amount of time that it took to get a replacement was also painfully slow. Not good. Buy a Crucial M4, which is what I did while I was waiting. The Crucial M4 is fast, and I've had no problems at all. Reply
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