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

Peak performance on the 120GB Vertex 3 is just as impressive as the 240GB pre-production sample as well as the m4 we just tested. Write incompressible data and you'll see the downside to having fewer active die, the 120GB drive now delivers 84% of the performance of the 240GB drive. In 3Gbps mode the 240 and 120GB drives are identical.

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

At high queue depths the gap between the 120 and 240GB Vertex 3s grows a little bit when we're looking at incompressible data.

Iometer - 4KB Random Read, QD=3

Random read performance is what suffered the most with the transition from 240GB to 120GB. The 120GB Vertex 3 is slower than the 120GB Corsair Force F120 (SF-1200, similar to the Vertex 2) in our random read test. The Vertex 3 is actually about the same speed as the old Indilinx based Nova V128 here. I'm curious to see how this plays out in our real world tests.

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 Write

Highly compressible sequential write speed is identical to the 240GB drive, but use incompressible data and the picture changes dramatically. The 120GB has far fewer NAND die to write to in parallel and in this case manages 76% of the performance of the 240GB drive.

Iometer - 128KB Sequential Read

Sequential read speed is also lower than the 240GB drive. Compared to the SF-1200 drives there's still a big improvement as long as you've got a 6Gbps controller.

The Vertex 3 120GB AnandTech Storage Bench 2011


View All Comments

  • semo - Thursday, April 07, 2011 - link

    The real issue was that it wasn't just a few % difference. Some V2 drives were nowhere near the rated capacity with the 25nm NAND. So if you bought 2 V2 drives and they happen to be different versions, RAID wouldn't work. There is still no way to confirm if the V2 you are trying to buy is one of the affected drives as OCZ haven't issued a recall or taken out affected drives from retail shelves. Best way to avoid unnecesary hassle is not to buy OCZ at all. Corsair did a much better job at informing the customer about the transition:

    The performance difference was higher than a few % as well.
  • casteve - Thursday, April 07, 2011 - link

    Great review! Thanks for carrying the 120GB torch :)

    I'd love to see a couple of HDDs added to the 2011 bench (like they are in the 2010 bench) to keep the perspective in play.* Most people are still moving from an HDD to an SSD and not just upgrading their SSD's.

    * stuff a 120GB SSD in yer laptop for $200 to replace a 5400rpm HDD and improve gaming IOPS by 5x is more impressive than replacing an existing 120GB SSD with a newer one for $250 and improve gaming IOPS by 10%. Extreme example...but you get the idea.
  • Gasaraki88 - Thursday, April 07, 2011 - link

    I want to thank you for writing this article and keeping the companies honest. Without smart people like you, companies will overstate performance and to the common person it will look fine because we don't have the proper tools to test.

    I'll been reading Anandtech for 11 years now. The quality is still top notch unlike some other sites I used to go to.
  • cknobman - Thursday, April 07, 2011 - link

    Dont buy OCZ products.

    Anand and countless consumer reviews from Newegg have proved that OCZ does not put out a consistent and reliable level of product.

    Im not one for rolling the crap dice with my hundreds of hard earned dollars.
  • hackztor - Thursday, April 07, 2011 - link

    LOL, okay go spend your hard earned money on last year performance intel new drives. Reply
  • seapeople - Thursday, April 07, 2011 - link

    Wow you got him there! Yeah, why doesn't he just buy an Intel drive. That would be funny because then he would have to wait 5.6 seconds to open Photoshop instead of 5.2 seconds. Or it would take a full 33 seconds to reboot instead of 35 seconds. I bet he's so unintelligent that he would actually accept crappy last-generation solid state drive performance like that at a lower price. Reply
  • semo - Friday, April 08, 2011 - link

    Corsair, patriot and many other SSD makers use SF controllers. You just have to be sure you know what firmware you're getting. You have to be much more careful with OCZ as you can't trust them to sell you what they claim on the box. Reply
  • Stargrazer - Thursday, April 07, 2011 - link

    It's awesome that you're reviewing the 120GB version first. It's the version that I believe most people would be most interested in getting, so it's great that we'll be able to see how it performs, rather than only seeing the higher numbers of a ~256GB version that's so expensive that most people would never get it. It's fantastic even. Did I mention that it's awesome?

    Unfortunately, since the ~128GB versions haven't always been reviewed in the past, this also means that we don't really have much to compare the numbers to. How do we know if the 120GB Vertex 3 is competitive if we don't know the performance of its competitors?

    I can understand if it might take a while to get the numbers for comparable versions of the 510, 310 and m4 (though I really hope that in the future you continue to press on for getting ~128GB versions in time for the initial reviews), but would it at least be possible to get the complete numbers for the 128GB version of the RealSSD C300? For some reason it doesn't seem to be in the IOmeter tests.

    Oh. Isn't it time that you stopped using "I didn't expect to have to debut this so soon" in the introduction to the 2011 Storage Bench? :)
  • KenPC - Thursday, April 07, 2011 - link

    A humorous thought of little relevance. but.. if OCZ rebrands the Vertex 2 as the 2b to solidify performance specs. then as I shop I will be thinking....

    Is this OCZ drive a 2b or not 2b, that is the question.....
  • Omid.M - Thursday, April 07, 2011 - link

    They saw Anand's Vibrams and knew he meant business (casual).


Log in

Don't have an account? Sign up now