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

  • Shadowmaster625 - Tuesday, May 24, 2011 - link

    A pair of 60GB Agility 2 costs a lot less and should mop the floor with these. We need sata 3 like we needed sata 2 in 2005. Reply
  • Arbie - Tuesday, May 24, 2011 - link

    Other sites can provide useful comparative info on SSDs, but what really sets Anandtech apart is depth of knowledge and especially the custom test suites you have developed. They tell the story that I as a home desktop user need to know, and nobody else has anything like them. Reply
  • eric appla - Tuesday, May 24, 2011 - link

    I wonder if OCZ did something to improve reliability. I have Vertex 2 and it is pain in the back part of my body. I have already third as I had to RMA two of them already and big reseller shops are reporting return ratios as high as 15% for OCZ vertex II series.
    I wish I never bought it really. Especially in combination with DELL laptop it looks like total fail.
  • bji - Tuesday, May 24, 2011 - link

    Yeah I stay away from OCZ products because I have read far too many anecdotal stories like yours, especially in the reviews of OCZ products on newegg, to feel comfortable buying anything from OCZ. All manufacturers have a percentage of failed parts and that's to be expected; but OCZ always seems to have alot more reports of problems than other vendors. Until that changes for a while, I will not buy anything from OCZ. Reply
  • LuvKush - Tuesday, May 24, 2011 - link

    I agree, we really want to see the corsair force 3 or GT's in action 120gb version and 240gb Thanks Anand. Been waiting for those reviews. Also is the 128gb M4 suffer the same fate as the ocz vertex 3 120gb version? as the nands are cut in half and lost performance too? I have the crucial m4 128gb and would love to know if the performance loss is as bad as the 120gb vertex 3 is to the 240gb vertex 3. Thanks again! Reply
  • StuffOfInterest - Tuesday, May 24, 2011 - link

    I'd like to see the 60GB Agility benchmarked in a Z68 Smart Response Technology (SRT) configuration. The early tests of SRT showed quite a few tradeoffs between R/W performanc and capacity. Having a SATA-III drive right at the size max for SRT could provide for an interesting comparison against Intels 311 which was designed specifically for SRT. Reply
  • iwod - Tuesday, May 24, 2011 - link

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

    Shouldn't it be 120GB Vertex 3?
  • iwod - Tuesday, May 24, 2011 - link

    It would be much more interesting to see how 60GB perform, especially against the Crucial M4 64GB SSD. Reply
  • Oxford Guy - Tuesday, May 24, 2011 - link

    I don't understand why this isn't included in the charts, particularly the current "E" model with 25nm 64-bit NAND. Reply
  • Oxford Guy - Tuesday, May 24, 2011 - link

    In fact, there isn't a single Vertex 2 drive in these charts. It's bizarre.

    People would like to see how the 240 GB Vertex 2 fares against the Vertex 3.

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