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


View All Comments

  • dj christian - Thursday, November 29, 2012 - link

    "Now, according to Anandtech, a 256GB-labelled SSD actually *HAS* the full 256GiB (275GB) of flash memory. But you lose 8% of flash for provisioning, so you end up with around 238GiB (255GB) anyway. It displays as 238GB in Windows.

    If the SSDs really had 256GB (238GiB) of space as labelled, you'd subtract your 8% and get 235GB (219GiB) which displays as 219GB in Windows. "

    Uuh what?
  • sully213 - Wednesday, November 28, 2012 - link

    I'm pretty sure he's referring to the amount of NAND on the drive minus the 6.8% set aside as spare area, not the old mechanical meaning where you "lost" disk space when a drive was formatted because of base 10 to base 2 conversion. Reply
  • JellyRoll - Tuesday, November 27, 2012 - link

    How long does the heavy test take? The longest recorded busy time was 967 seconds from the Crucial M4. This is only 16 minutes of activity. Does the trace replay in real time, or does it run compressed? 16 minutes surely doesnt seem to be that much of a long test. Reply
  • DerPuppy - Tuesday, November 27, 2012 - link

    Quote from text "Note that disk busy time excludes any and all idles, this is just how long the SSD was busy doing something:" Reply
  • JellyRoll - Tuesday, November 27, 2012 - link

    yes, I took note of that :). That is the reason for the question though, if there were an idea of how long the idle periods were we can take into account the amount of time the GC for each drive functions, and how well. Reply
  • Anand Lal Shimpi - Wednesday, November 28, 2012 - link

    I truncate idles longer than 25 seconds during playback. The total runtime on the fastest drives ends up being around 1.5 hours.

    Take care,
  • Kristian Vättö - Wednesday, November 28, 2012 - link

    And on Crucial v4 it took 7 hours... Reply
  • JellyRoll - Wednesday, November 28, 2012 - link

    Wouldn't this compress the QD during the test period? If the SSDs recorded activity is QD2 for an hour, then the trace is replayed quickly this creates a high QD situation. QD2 for an hour compressed to 5 minutes is going to play back at a much higher QD. Reply
  • dj christian - Thursday, November 29, 2012 - link

    What is QD? Reply
  • doylecc - Tuesday, December 04, 2012 - link

    Que Depth Reply

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