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

Desktop Iometer - 4KB Random Write

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

Random performance is strong when dealing with an empty drive but as the two previous pages show the big picture isn't as pleasant. The difference between 64Gbit and 128Gbit NAND is very clear here as the M550 is up to twice as fast as the M500 at the smaller capacities.

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

Sequential speeds are up quite a bit from the M500 as well but the read performance is still a bit lacking.

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. Again, the M550 shows a decent improvement over the M500, particularly at the lower capacities.

Incompressible Sequential Read Performance

Incompressible Sequential Write Performance

AnandTech Storage Bench 2013 Performance vs Transfer Size
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  • hojnikb - Tuesday, March 18, 2014 - link

    You forgot plextor m5pro xtreme in top tier :)
  • extide - Tuesday, March 18, 2014 - link

    Oh Yeah, totally forgot about that one :)
  • kyuu - Tuesday, March 18, 2014 - link

    The 840 EVO is a damn good performer, and the Seagate 600 gives you a damn good capacity/price ratio (I bought the 240GB for $130 the other week). Otherwise, looks good.
  • jed22281 - Friday, March 21, 2014 - link

    When it comes to perf. "overall", not all those are absolute top-tier, some of them should be in a upper-mid-tier category.
    There's only approx. 3 that could truly be considered as absolute top-tier: Extreme II & Ocz 150 are 2 of them.
  • jay401 - Tuesday, March 18, 2014 - link

    Regarding your price comparison chart on the Final Words page: At the time of publication, the Samsung 840 EVO 256GB drive is listed at $139.99 on Amazon.com and has been for a couple days.
  • Kristian Vättö - Tuesday, March 18, 2014 - link

    We are only using NewEgg for comparisons as otherwise it takes ages to do the chart. Besides, the pricing can change on daily basis so it would only be accurate for a short while. The idea is to give a rough idea of pricing -- ultimately every buyer should do their decision based on the current deals.
  • jay401 - Wednesday, March 19, 2014 - link

    Understood. In this case though, Amazon's had it that cheap for about a week now. :)
  • venk90 - Tuesday, March 18, 2014 - link


    The 512 GB crucial m550 SSD is listed at 169$ !!
    Buy it now before the prices are corrected !
  • dave_the_nerd - Tuesday, March 18, 2014 - link

    Wow... bought. Worst case, I'll return it, but... damn.
  • venk90 - Tuesday, March 18, 2014 - link

    I bought 20 !
    Going to E-Bay all of them or return it worst case !

    Greedy me ? Haha !

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