This is shaping up to be the busiest month in the SSD frontier for ages. Intel released its new flagship SSD 730 series just a couple of weeks ago and there are at least two more releases coming in the next few weeks...but today it's Crucial's turn to up the ante.

Unlike many OEMs, Crucial has more or less had only one active series in its SSD portfolio at a time. A few years ago this approach made sense because the SSD market as a whole mainly focused on enthusiasts and there was no real benefit to a tiered lineup. As the market has matured and prices have dropped over time, we are now in a situation similar to other components: there is the high volume mainstream market where price is the key and the higher margin enthusiast/professional market where performance and features matter. Covering both of these markets with a single product is hard because in order to compete in price, it's usually necessary to use lower quality parts, which in turn affects performance and features.

With the M500 Crucial was mainly targeting the mainstream market. The performance was mostly better than in the m4 days but only mediocre compared to other SSDs in the market. The introduction of the likes of the SanDisk Extreme II, Seagate SSD 600, and OCZ Vector 150 has upped the ante even more in the enthusiast segment and it has become clear that the M500 has no place there. To stay competitive in all product areas, Crucial is now launching the big brother to their M500: the M550.

EDIT: Just to clarify, the M500 will continue to be available and the M550 is merely a higher performing option at slightly higher price.

With 64Gbit NAND, 240/256GB was usually the sweet spot in terms of price and performance. That combination offered enough NAND die to saturate the SATA 6Gbps as well as the controller's/firmware's potential, but with the M500 this was no longer the case thanks to the usage of 128Gbit NAND. With a die that was twice the capacity, you only needed half the dies to build a 240/256GB SSD. As NAND parallelism is a major source of SSD performance, this meant a decrease in performance at 240/256GB and you would now have to go to 480/512GB to get the same level of performance that 240/256GB offered with 64Gbit NAND.

The use of 128Gbit NAND was one of the main reasons for the M500's poor performance, and with others staying with 64Gbit NAND, that backfired on Crucial in terms of performance (more on this later). Since it's not possible to magically decrease program times or add parallelism, Crucial decided to bring back the 64Gbit NAND in the lower capacity M550s. Here's how the new and old models compare:

Crucial M550 vs Crucial M500
  M550 M500
Controller Marvell 88SS9189 Marvell 88SS9187
NAND Micron 64/128Gbit 20nm MLC Micron 128Gbit 20nm MLC
Capacity 128GB 256GB 512GB 1TB 120GB 240GB 480GB 960GB
Sequential Read 550MB/s 500MB/s
Sequential Write 350MB/s 500MB/s 130MB/s 250MB/s 400MB/s
4KB Random Read 90K IOPS 95K IOPS 62K IOPS 72K IOPS 80K IOPS
4KB Random Write 75K IOPS 80K IOPS 85K IOPS 35K IOPS 60K IOPS 80K IOPS
Endurance 72TB (~66GB/day) 72TB (~66GB/day)
Warranty Three years Three years

The 128GB and 256GB models are now equipped with 64Gbit per die NAND while 512GB and 1TB models use the same 128Gbit NAND as in the M500. What this means is that the 128GB and 256GB models are much more competitive in performance because the die count is twice that of the same capacity M500 drives. You get roughly the same performance with both 256GB and 512GB models (unlike the nearly 50% drop in write performance like in the M500) and the 128GB actually beats the 240GB M500 in all metrics. There is obviously some firmware tweaking involved as well and the bigger capacities get a performance bump too, although it's much more moderate compared to the smaller capacities.

Another difference is the controller. Compared to the NAND, this isn't as substantial a change because the Marvell 9189 is more of an updated version of the 9187 and the only major upgrades are support for LPDDR and better optimization for DevSleep, both of which help with power consumption and can hence extend the battery life.

Crucial M550 Specifications
Capacity 128GB 256GB 512GB 1TB
Controller Marvell 88SS9189
NAND Micron 64Gb 20nm MLC Micron 128Gb 20nm MLC
Cache (LPDDR2-1066) 512MB 512MB 512MB 1GB
Sequential Read 550MB/s 550MB/s 550MB/s 550MB/s
Sequential Write 350MB/s 500MB/s 500MB/s 500MB/s
4KB Random Read 90K IOPS 90K IOPS 95K IOPS 95K IOPS
4KB Random Write 75K IOPS 80K IOPS 85K IOPS 85K IOPS

Similar to the earlier drives, Crucial continues to be Micron's household brand whereas OEM drives will be sold under Micron's name. It's just a matter of branding and there are no differences between the retail and OEM drives other than an additional 64GB model for OEMs. 

Crucial switches back to binary capacities in the M550 and with the 1TB model you actually get the full 1024GB of space (though Crucial lists it as 1TB for marketing reasons, and there's still 1024GiB of actual NAND). The reason behind this isn't a reduction in over-provisioning but merely a more optimized use of RAIN (Redundant Array of Independent NAND).

RAIN is similar to SandForce's RAISE and the idea is that you take some NAND space and dedicate that to parity. Almost every manufacturer is doing this at some level nowadays since the NAND error and failure rates are constantly increasing as we move to smaller lithographies. When the M500 came out the 128Gbit NAND was very new and Crucial/Micron wanted to play it safe and dedicated quite a bit of NAND for RAIN to make sure the brand new NAND wouldn't cause any reliability issues down the road. In a year a lot happens in terms of maturity of a process and Crucial/Micron are now confident that they can offer the same level of endurance and reliability with less parity. The parity ratio is 127:1, meaning that for every 127 bits there is one parity bit. This roughly translates to 1GiB of NAND reserved for parity in the 128GB M550 and 2GiB, 4GiB and 8GiB for the higher capacities.

Feature wise the M550 adopts everything from the M500. There is TCG Opal 2.0 and IEEE-1667 support, which are the requirements for Microsoft's eDrive encryption. Along with that is full power loss protection thanks to capacitors that provide the necessary power to complete in-progress NAND writes in case of power loss.

Update: Micron just told us that in addition to the capacitors there is some NAND-level technology that makes the M550 even more robust against power losses. We don't have the details yet but you'll be the first to know once we got them.

NAND Configurations
Raw NAND Capacity 128GiB 256GiB 512GiB 1024GiB
RAIN Allocation ~1GiB ~2GiB ~4GiB ~8GiB
Over-Provisioning 6.1% 6.1% 6.1% 6.1%
Usable Capacity 119.2GiB 238.4GiB 476.8GiB 953.7GiB
# of NAND Packages 16 16 16 16
# of NAND Die per Package 1 x 8GiB 2 x 8GiB 2 x 16GiB 4 x 16GiB


Test System

CPU Intel Core i5-2500K running at 3.3GHz
(Turbo and EIST enabled)
Motherboard AsRock Z68 Pro3
Chipset Intel Z68
Chipset Drivers Intel + Intel RST 10.2
Memory G.Skill RipjawsX DDR3-1600 4 x 8GB (9-9-9-24)
Video Card Palit GeForce GTX 770 JetStream 2GB GDDR5
(1150MHz core clock; 3505MHz GDDR5 effective)
Video Drivers NVIDIA GeForce 332.21 WHQL
Desktop Resolution 1920 x 1080
OS Windows 7 x64

Thanks to G.Skill for the RipjawsX 32GB DDR3 DRAM kit

NAND Lesson: Why Die Capacity Matters
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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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