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.

Desktop Iometer - 128KB Sequential Read (4K Aligned)

Low queue depth sequential read performance is among the better drives, but still slightly behind Samsung.

Desktop Iometer - 128KB Sequential Write (4K Aligned)

Write performance continues to be the Vector's strong suit, here only Intel's SSD 520 with easily compressed data pulls ahead.

AS-SSD Incompressible Sequential Performance

The AS-SSD sequential benchmark uses incompressible data for all of its transfers. The result is a pretty big reduction in sequential write speed on SandForce based controllers.

Incompressible Sequential Read Performance - AS-SSD

High queue depth sequential IO shows significant clustering at the top of the charts thanks to the limits of 6Gbps SATA. The Vector pushes performance pretty much as fast as possible here.

Incompressible Sequential Write Performance - AS-SSD

Switching to writes does shake loose some of the weaker competitors, but the Vector and 840 Pro still emerge as the strongest. Corsair's Neutron GTX does very well here.

Random IO Performance Performance vs. Transfer Size
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  • melgross - Wednesday, November 28, 2012 - link

    What does that mean; usable space? Every OS leaves a different amount after formatting, so whether the drive is rated by GB or GiB, the end result would be different. Normally, SSD's are rated as to the around seen by the OS, not by that plus the around overrated. So it isn't really a problem.

    Actually, the differences we're talking about isn't all that much, and is more a geeky thing to concern oneself with more than anything else. Drives are big enough, even SSD's, so that a few GB's more or less isn't such a big deal.
    Reply
  • Kristian Vättö - Wednesday, November 28, 2012 - link

    An SSD can't operate without any over-provisioning. If you filled the whole drive, you would end up in a situation where the controller couldn't do garbage collection or any other internal tasks because every block would be full.

    Drive manufacturers are not the issue here, Microsoft is (in my opinion). They are using GB while they should be using GiB, which causes this whole confusion. Or just make GB what it really is, a billion bytes.
    Reply
  • Holly - Thursday, November 29, 2012 - link

    Sorry to say so, but I am afraid you look on this from wrong perspective. Unless you are IT specialist you go buy a drive that says 256GB and expect it to have 256GB capacity. You don't care how much additional space is there for replacement of bad blocks or how much is there for internal drive usage... so you will get pretty annoyed by fact that your 256GB drive would have let's say 180GB of usable capacity.

    And now this GB vs GiB nonsense. From one point of view it's obvious that k,M,G,T prefixes are by default *10^3,10^6,10^9,10^12... But in computers capacity units they used to be based on 2^10, 2^20 etc. to allow some reasonable recalculation between capacity, sectors and clusters of the drive. No matter what way you prefer, the fact is that Windows as well as many IDE/SATA/SAS/SCSI controllers count GB equal to 2^30 Bytes.

    Random controllers screenshots from the internet:
    http://www.cisco.com/en/US/i/100001-200000/190001-...
    http://www.cdrinfo.com/Sections/Reviews/Specific.a...
    http://i.imgur.com/XzVTg.jpg

    Also, if you say Windows measurement is wrong, why is RAM capacity shown in 'GB' but your 16GB shown in EVERY BIOS in the world is in fact 16384MiB?

    Tbh there is big mess in these units and pointing out one thing to be the blame is very hasty decision.

    Also, up to some point the HDD drive capacity used to be in 2^k prefixes long time ago as well... still got old 40MB Seagate that is actually 40MiB and 205MB WD that is actually 205MiB. CD-Rs claiming 650/700MB are in fact 650/700MiB usable capacity. But then something changed and your 4.7GB DVD-R is in fact 4.37GiB usable capacity. And same with hard discs...

    Try to explain angry customers in your computer shop that the 1TB drive you sold them is 931GB unformatted shown both by controller and Windows.

    Imho nobody would care slightest bit that k,M,G in computers are base 2 as long as some marketing twat didn't figure out that his drive could be a bit "bigger" than competition by sneaking in different meaning for the prefixes.
    Reply
  • jwilliams4200 - Thursday, November 29, 2012 - link

    It is absurd to claim that "some marketing twat didn't figure out that his drive could be a bit "bigger" than competition by sneaking in different meaning for the prefixes".

    The S.I. system of units prefixes for K, M, G, etc. has been in use since before computers were invented. They have always been powers of 10. In fact, those same prefixes were used as powers of ten for about 200 years, starting with the introduction of the metric system.

    So those "marketing twats" you refer to are actually using the correct meaning of the units, with a 200 year historical precedent behind them.

    It is the johnny-come-latelys that began misusing the K, M, G, ... unit prefixes.

    Fortunately, careful people have come up with a solution for the people incorrectly using the metric prefixes -- it is the Ki, Mi, Gi prefixes.

    Unfortunately, Microsoft persists in misusing the metric prefixes, rather than correctly using the Ki, Mi, Gi prefixes. That is clearly a bug in Microsoft Windows. Kristian is absolutely correct about that.
    Reply
  • Holly - Friday, November 30, 2012 - link

    How much RAM does your bios report you have?
    Was the BIOS of your motherboard made by Microsoft?
    Reply
  • jwilliams4200 - Friday, November 30, 2012 - link

    Would you make that argument in front of a judge?

    "But judge, lots of other guys stole cars also, it is not just me, so surely you can let me off the hook on these grand-theft-auto charges!"
    Reply
  • Touche - Saturday, December 01, 2012 - link

    No, he is right. Everything was fine until HDD guys decided they could start screwing customers for bigger profits. Microsoft and everyone else uses GB as they should with computers. It was HDD manufacturers that caused this whole GB/GiB confusion regarding capacity. Reply
  • jwilliams4200 - Saturday, December 01, 2012 - link

    I see that you are a person who never lets the facts get in the way of a conspiracy theory. Reply
  • Touche - Monday, December 03, 2012 - link

    http://betanews.com/2006/06/28/western-digital-set... Reply
  • Holly - Monday, December 03, 2012 - link

    Well, 2^10k prefixes marked with 'i' were made in a IEC in 1998, in IEEE in 2005, alas the history is showing up frequent usage of both 10^3k and 2^10k meanings. Even with IEEE passed in 2005 it took another 4 years for Apple (who were the first with OS running with 2^10k) to turn to 'i' units and year later for Ubuntu with 10.10 version.

    For me it will always make more sense to use 2^10k since I can easily tell size in kiB, MiB, GiB etc. just by bitmasking (size & 11111111110000000000[2]) >> 10 (for kiB). And I am way too used to k,M,G with byte being counted for 2^10k.

    Some good history reading about Byte prefixes can be found at http://en.wikipedia.org/wiki/Timeline_of_binary_pr... ...

    Ofc, trying to reason with people who read several paragraph post and start jumping around for one sentence they feel offended with is useless.

    But honestly even if kB was counted for 3^7 bytes it wouldn't matter... as long as everyone uses the same transform ratio.
    Reply

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