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). We perform three concurrent IOs and run the test for 3 minutes. The results reported are in average MB/s over the entire time.

Desktop Iometer - 4KB Random Read

Random read performance remains mostly unchanged. The 512GB MX100 appears to be slightly faster than the M550 while the 256GB version is a few megabytes slower.

Desktop Iometer - 4KB Random Write

Desktop Iometer - 4KB Random Write (QD=32)

Random write performance, on the other hand, is slightly up at the lower queue depths. This is likely due to firmware optimizations as the performance is up regardless of the capacity, although once the queue depth is increased the 256GB version falls behind due to the more limited amount of NAND die.

Sequential Read/Write Speed

To measure sequential performance we run 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

Sequential performance is also up by a bit, although the difference isn't dramatic.

Desktop Iometer - 128KB Sequential Write

AS-SSD Incompressible Sequential Read/Write 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

Incompressible Sequential Write Performance

AnandTech Storage Bench 2011 Performance vs. Transfer Size


View All Comments

  • extide - Monday, June 02, 2014 - link

    Wow, 256Gbit dies! That would mean up to 2TB in a standard 2.5" SSD -- Crazy! Reply
  • hojnikb - Monday, June 02, 2014 - link

    Actually one could fit 4TB into a standard 2.5" (or even 8GB when using 32 packages) but the problem is, as far as i can tell, no single controller can adress so much space. Reply
  • hojnikb - Monday, June 02, 2014 - link

    *TB obviously :) Reply
  • extide - Monday, June 02, 2014 - link

    Yeah but it's a chicken and egg thing I think. There seems to be a max price cap of about $600 for these SSD's, and so for 64gbit NAND that was ~512GB and 128Gbit NAND it is about 1TB. When they design a controller to exist during the lifetime of 256Gbit NAND there is a good chance that someone is actually going to make a 2TB drive because that much NAND would then fit inside that 'max price' so they will design the controller for that max amount. And in the same vein a contrller for the 128Gbit era would be 'OK' with a 1TB max.... if that makes sense, heh. Reply
  • hojnikb - Monday, June 02, 2014 - link

    Also, there is already 2TBs drives out thre on the old 64Gbit flash :) Reply
  • danwat1234 - Monday, January 26, 2015 - link

    Intel S3500 2TB exists, not sure if it works in laptops though Reply
  • fruitcrash - Wednesday, June 04, 2014 - link

    It's not that you can't address it (for ONFI NAND you can use the Volume Select command), but that you can't have more than about 8 chips on a channel because of capacitive loading. Reply
  • extide - Monday, June 02, 2014 - link

    NOTE: I am talking about the future NAND, NOT what is used in this drive. Reply
  • hojnikb - Monday, June 02, 2014 - link

    Still, 256Gbit dies can can't help you much, if controller can't adress that much space. As i've said above, once could fit 4-8TB of flash, it's just isn't possible yet. Reply
  • hojnikb - Monday, June 02, 2014 - link

    Any details on the 128GB version ?
    I've read somewhere, that it will be using the old 20nm flash...

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