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 - Wednesday, March 19, 2014 - link

    Oh snap, i forgot to reply to @beginner99 :)
  • emn13 - Wednesday, March 19, 2014 - link

    The conclusion of this article is at odds with the benchmarks it includes. There's just a 20% performance difference on the heavy-load test between the 840 EVO and M550 1TB drives, less in lighter workloads. I don't believe a 20% performance difference is perceptible in practice, unless you're really doing long-duration purely disk-limited batch processing, and even then it's not exactly a very interesting difference.

    The appropriate conclusion here is: *any* reasonably modern SSD is more that fast enough that even a heavy workload won't cause user-noticable performance differences. It just doesn't matter. Other factors (e.g. power consumption, power loss protection, price, reliability, support) are what matter.

    The article's conclusion simply doesn't make sense given the numbers shown here.
  • hojnikb - Wednesday, March 19, 2014 - link

    Well, there are some reasonably modern ssds, that user WILL notice the difference. Crucial V4 for expamle..
  • Kristian Vättö - Wednesday, March 19, 2014 - link

    Okay, I'll let Anand know that we no longer need to do reviews because all modern devices are already capable of Facebook, email and text processing.

    In a more serious note, it's true that for light users any modern SSD is fine and that is what I said in the final page:

    "If you're a light user and price is the key purchase factor, then the M500 suffices and saves you money."

    And that is the biggest problem I have with the M550. The M500 already does it for the mainstream user group and to be honest it is the drive I would buy given the current prices.

    However, the M550 doesn't cut it for the enthusiast/professional group who want the best IO performance. It does the job for sure but the enthusiast/professional kind of people usually like the idea of having the best money can buy, even if the differences in real world aren't that big. On the other hand, that's also the user group that can actually take advantage of the extra performance.

    I would argue that there is no middle ground in the SSD market. It's either the mainstream market where price is all that matters and that's where the M500 fits in perfectly. The high-end market is where the performance and features are the main element but the M550 isn't competitive there. Everything in the middle are kinda purposeless - some people will always buy them but they don't have any clear inducement to make them alluring.

    P.S. Don't take the first line too personally or seriously. Sometimes the comments just make me feel like everything is already enough for everyone and we don't need improved hardware.
  • hojnikb - Wednesday, March 19, 2014 - link

    Yeah exactly. m550 really seems kinda redundant (not implying, that better performance isn't good), considering its suppost to be a high performance drive, yet it really compets with mainstream at best.
    I think crucial need to work on firmware department, because as we've seen, there's lots to be squeezed out of this marvell controler. They already have great nand, they just need to make firmware better and they could easily compete in the highend segment.
    Well atleast thats what i think anyway..
  • Cerb - Sunday, March 23, 2014 - link

    Given that read and write latency is consistently higher than other SSDs, I'd bet much of the speed limitations are due to RAIN, which has to be handled in software by the SSD's controller. If so, newer faster controllers are what it would take to improve the speed by any great amount, without sacrificing that feature.
  • emn13 - Wednesday, March 19, 2014 - link

    I'm not saying you shouldn't review these things - I'm extremely interested in the results of these reviews. I'm saying that your own results don't back up your conclusions. It's not just light workloads where the difference is hard to notice - the anandtech 2013 "destroyer" - IIRC which writes a considerable amount, quite a bit more that a light, normal desktop workload (or frankly even a fairly heavy desktop workload) only shows a 20% performance difference. The performance consistency numbers at the steady state are just below 5000 iops, and that's actually slightly better than the EVO 840.

    Notably, there *are* SSD's which are quite a bit slower, and I'm sure there will be SSD's (or are, if you pay enough) that outclass the M550 - but I'm just not seeing that in these results.

    Sorry if I came across as ungracious - it's a little unfair in that I'm commenting now in that it seems I think the coverage is poor. But I'm commenting now, because this is one of the rare articles where I think anandtech's conclusions aren't reasonable. I love your coverage, particularly of SSD's, and have gladly learned a lot from all the in-depth analysis you've done.

    So please don't take this personally (I may have exagerrated) - I really don't understand how given essentially equivalent performance to the 840 EVO in practical terms (and slightly better @ steady state) you can call the performance all that disappointing. It's not a top-performer; but then, it's clearly aimed at the larger capacity/lower-price, and then I really don't see how this conclusion stacks up.
  • emn13 - Wednesday, March 19, 2014 - link

    Hmm, I've gotta admit however that the smaller variants are a lot more disappointing. I'm kind of surprised how *much* slower they are - the 256GB version is less than half as fast on the destroyer, which is really will be noticable :-).
  • Kristian Vättö - Wednesday, March 19, 2014 - link

    Oh, absolutely not. Justified feedback like yours is always welcome :)

    I guess the key here is that I was expecting this to be a high performance drive because that's what Crucial was touting when they briefed us. Obviously I expected the performance to be close to drives like SanDisk Extreme II and OCZ Vector 150 because those are what I categorize as high performance drives. However, what we got is a drive with mediocre performance that didn't meet the expectations I had in my mind, so I can't say I'm satisfied.

    That doesn't mean the M550 is bad because the price is very competitive but I still think it's rather redundant because the M500 is even more competitive in price. If the M550 was to replace the M500, then the scenario (and hence conclusion) would be different but as it stands the M500 will continue to be the king of value.

    The EVO is different in this regard because it was always supposed to be a value drive and Samsung has the 840 Pro to cater the high performance market.
  • nick2crete - Thursday, March 20, 2014 - link

    Kristian ,
    do you think that these performance issues can be minimized/fixed with new firmware(s) from Crucial ?

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