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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  • Hrel - Wednesday, April 2, 2014 - link

    no response? Cause I'd really like this explained. Consistency in these charts stays WAY over 100.
  • shatteredx - Thursday, May 8, 2014 - link

    Yeah I'm also confused by the conclusions in this article. The M550 consistency numbers look pretty... consistent!
  • Wolfpup - Monday, March 31, 2014 - link

    I can't remember if the M500 has capacitors to deal with power loss or not...suppose I should reread the review. Anyway I choose my 960GB M500 because at the time Intel was using Sandforce controllers, and there's no way I'd use a different brand when Crucial/Micron and Intel are making drives.

    While there are probably theoretically faster drives than my M500, it's not going to be anything obvious. I can't even really tell that my M500 is any faster than my M4 even though it is on paper.

    960GB on a relatively affordable SSD is awesome! Its literally at the point where I'd have had to go with a smaller drive to get a 7200RPM mechanical drive LOL
  • DKN - Wednesday, April 9, 2014 - link

    Latecomer to the discussion. I'm currently running a 240GB M500 drive in an old Lenovo T61p (Core2 Duo T8100). Changing from a 7200RPM HD to the SSD made all the difference in the world as far as day to day use of the laptop.

    Some things, like logging on are about 5x faster than with the HD. Other things are 10x or more faster, making this old laptop work better than some i7 machines with HDs in the office.

    Note that the T61p originally supported SATA 1 and with a BIOS upgrade, it's now SATA 2, so the transfer rates are in line with the capability of the SSD hardware. Purchasing a drive that can support SATA 3 transfer rates wouldn't do anything for the performance of this computer.

    The bottom line? While the enthusiast market is lusting for the latest i7 and graphics processor, there is a large market that just needs something better to make their computers work faster.

    I'm considering upgrading my two laptops at home with M500 drives. The slower machine with a 240GB and the faster (i7, 2nd Gen) with a 480GB.

    Crucial's decision to continue to market the M500 series makes perfect sense for 90% of the users, even if it isn't as fast as the M550.
  • stevo5800 - Thursday, April 17, 2014 - link

    Theres a 60% increase from an M500 and M550 random write but you guys say there is no increase in performance? LOL The average user probably just uses Windows and a few games, so all these drives would perform around the same in the end. Crucial's biggest issue was the lack of higher write speeds. On M500 and earlier write speeds where really low compared to other drives. Plus Crucial also beats some of the other drives in some of the tests here. Almost every SSD manufacturer makes at least 1 decent SSD now a days. Let's not also forget the M550 is brand new and there is still the chance of improvement in some speeds with a new firmware update, we've seen this before. Heck I still find my M4 speedy and it's got way lower specs then the M550. Personally I'm buying a M550 256GB, I'm going for write speeds.
  • AhDah - Thursday, May 15, 2014 - link

    Hello all,
    I want to buy my first SSD
    I'm deciding between Crucial M550 1TB and Samsung 840 Evo 1TB

    On the Samsung 840 Evo, the TRIM validation graph shows a tremendous performance drop after a few gigs of writes, even after TRIM pass, the write speed is only 150MBps.
    Does this mean once the drive is 75%-85% filled up, the write speed will always be slow?

    Crucial M550 on the other hand, has a consistent write speed according to the TRIM validation graph.

    Should I get the Crucial M550 because of this?
  • critter13 - Thursday, May 15, 2014 - link

    I have a 2007 MBP which is obviously SATA II. Is it worth getting a m550 or 840 EVO or will I not see the extra speed? should I save a little money and just go with the m500?
  • SyndromeOCZ - Friday, May 30, 2014 - link

    Seriously why do you make the title of the article a link? Ok if it was a link that actually went anywhere but a link that goes directly to the page I'm viewing. Doing this makes it about 1000 times harder to copy paste parts out of the title, forcing me to have to go through the article to find the part I want to copy. Which in turn forces me to want to never come back to Anandtech again. Just my $0.02
  • ayejay_nz - Sunday, February 15, 2015 - link

    Any word on whether the MU02 firmware update, released 01/8/2015, for this drive boosted performance?

    The release notes can be found here - http://www.crucial.com/wcsstore/CrucialSAS/firmwar...

    I'm not sure if the items they've listed as improving would increase performance?
  • pokazene_maslo - Tuesday, October 3, 2017 - link

    In changelog they mentioned improved power efficiency. Could anyone test power consumption in idle after FW upgrade?

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