Samsung’s 850 EVO M.2 solid-state drive reviewed

When we reviewed Samsung’s 850 EVO SSD last year, we commented on its remarkably compact internals. Although the drive comes in a standard 2.5″ case, the underlying circuit board occupies a fraction of that footprint. It was only a matter of time before Samsung rolled out miniaturized versions designed for smaller mSATA and M.2 form factors. And here they are:

mSATA (left), M.2 (middle), and 2.5″ (right) flavors of the 850 EVO

Apart from conforming to smaller form factors, the mini EVOs are identical to their full-sized siblings. They use the same 3D V-NAND with 32 layers and three bits per cell, and they accelerate writes with the same SLC caching scheme. They also use the same Samsung controllers. As in the 2.5″ lineup, the 120-500GB versions have the latest MGX chip, while the 1TB sports MEX silicon from the 850 Pro. The dual-core MGX controller isn’t as powerful as the triple-core MEX chip, but Samsung says it’s fast enough to deliver full performance at lower capacities.

Both controllers have SATA interfaces, so they can’t hook into the PCIe lanes available in some M.2 and mSATA slots. (mSATA shares a physical connector with mini PCIe cards.) The mini EVOs require slots with built-in SATA connectivity.

The 850 EVO mSATA scales all the way up to 1TB, while the M.2 tops out at 500GB. At only 80 mm long, the M.2 2280 “gumstick” apparently lacks the land mass to house 1TB of flash. The M.2 standard includes provisions for longer 22110 drives, so perhaps we’ll see a super-sized option eventually.

Apart from a few minor differences, the mini EVOs have identical performance ratings to their full-sized counterparts. They have the same AES encryption support, complete with the TCG Opal and IEEE compliance required by Microsoft’s eDrive spec. And they’re covered by the same endurance ratings, which promise 70TB of total writes for the 120GB and 250GB drives and 150TB for the larger sizes. That works out to 39GB and 84GB per day, respectively, for the length of the five-year warranty. Which is an awful lot.

  2.5″ mSATA M.2
120GB $74.99 $89.99 $89.99
250GB $109.99 $134.99 $134.99
500GB $194.99 $229.99 $249.99
1TB $389.99 $449.99 NA

Most of the fun-sized 850 EVOs are already listed at Newegg. They’re priced at a premium over the 2.5″ alternatives, but that’s also true of mSATA flavors of the old 840 EVO. With comparatively little competition in the mini SSD arena (at least among drives sold directly to consumers), prices tend to be a bit higher.

Since our original 850 EVO review already explores the drive’s performance in great detail, there’s no need to put the new family members through the wringer. We ran the 850 EVO M.2 250GB against its SATA counterpart in a handful of IOMeter tests and, well, see for yourself:





Clicking the buttons below the graphs switches between queue depths, but there’s little point. The two drives perform almost identically in these sequential and random tests.



They shadow each other under sustained and scaling loads, as well.

So there you have it. Samsung has officially rolled out mini versions of the 850 EVO. The drives have smaller M.2 and mSATA form factors, and they’re a little pricier than the 2.5″ versions that have been circulating since late last year.  But they’re pretty much identical otherwise.

Users can look forward to strong all-around performance and low power consumption, which is a good combo for mobile and small-form-factor systems that require mini drives. Given the price premium and the lack of PCIe connectivity, though, there’s little reason for folks with spare drive bays to downsize from the 2.5″ original.

Comments closed
    • balanarahul
    • 5 years ago

    Going forward I think M.2 drives should be the standard and there should be cheap M.2 to 2.5/3.5 convertors.

    • Chrispy_
    • 5 years ago

    Wow, I never realised how badly the TLC EVO drives suck under sustained workloads; A drop from 75K IOPS to 5K iops after just one minute of activity?

    No thanks. I’ll stick to a drive that uses far faster MLC if you’re going to charge MLC prices for you TLC products anyway….

      • MadManOriginal
      • 5 years ago

      It’s the SLC cache, and it is smaller on the 250GB model so it drops down sooner than 500GB+ models (check out various drives here: [url<]https://techreport.com/review/28032/a-fresh-look-at-storage-performance-with-pcie-ssds/3).[/url<] Anyway, the sustained performance of comparable sized consumer-oriented MLC drives isn't especially better. It would be nice if Samsung didn't think their drives deserved such a premium, although street/deal prices reflect reality - at least the 850 EVO has the performance to go along with its price premium.

        • Chrispy_
        • 5 years ago

        I know sub-5K IOPS is normal for sustained loads, it’s more that most Samsung drives look bad in comparison to the competition;

        Almost everything non-Samsung manages at least 100s before they have a performance nosedive, The equivalent Samsungs nosedive in under a minute, some in around 15s (1TB EVO excepted)

        15s of small writes is well within the realm of consumer usage, 2m of small writes less so.

          • MadManOriginal
          • 5 years ago

          It’s not the equivalent drive size, which I specifically mentioned for that reason. The larger review I linked has 500GB consumer drives, the m.2/mSATA tested here are 250GB.

    • albundy
    • 5 years ago

    no XP941 comparison? At least whoever created the connector made it easy to detect what type it is…single notch is pci-e, two notches is old school slower sata.

    • ronch
    • 5 years ago

    Hey Samsung, how about fixin’ the 840 EVO first, eh?

      • DPete27
      • 5 years ago

      I’ll get to test a Sandisk Ultra II this weekend that’s been sitting idle/off for 3ish months. Cant wait to see if its the TLC nand or the controller that’s creating the problem.

    • Thresher
    • 5 years ago

    I understand the difference between mSATA and PCI-E. That’s about as far as I can get though.

    I have no idea what will work in what slot. If the whole thing is confusing to me, who has a little more knowledge than the average consumer, this is going to be mindblowing to someone just out to add an SSD to their system.

    This whole thing has been a cluster**** of interfaces, sockets, and bus types.

    I have an Asus Z97 Deluxe board. I can’t make heads or tails out of what types of drives will work onboard and the documentation doesn’t explain it. They call it an “M.2 Socket 3”. Looking that up on the internet does not bring up any useful information. Without doing any deep research, I have no idea what SSDs will fit in there or which ones I should get for top performance.

    I hope they get this crap all sorted out, but they really screwed this up.

      • MadManOriginal
      • 5 years ago

      I agree, the mish-mash of physical, electrical, and logical interfaces is pretty stupid. Perhaps it was somewhat ok when the likely use was in OEM laptop systems only so end-users wouldn’t have to deal with it, but when you can’t even easily find out what goes with what it’s a pain in the ass; heck, it even makes discussing them annoying because you have to be really precise with the terms to be accurate.

      • ronch
      • 5 years ago

      Yup, I’ve been feeling the same thing. Hopefully, by the time I’m out for a new SSD they would’ve sorted this out already.

      • DevilsCanyonSoul
      • 4 years ago

      I own the same board and went through the frustration of figuring out “what’s what” until I finally confirmed my suspicions with a pretty thorough Asus tech on the phone. The Deluxe supports all the SATA based M.2’s and will cap-out at ~ 500 MB/sec. I tried a Plextor PCIE and it was a nightmare to get configured so back it went! Most recently I tried the Kingston Hyper and being a PCIE based M.2, it yielded ~700 MB/sec but I noticed fairly quickly that it ran substantially hotter than the Intel 530 I had been using. I still wanted a 512 GB space, so I settled for the Samsung EVO SATA unit and haven’t looked back. 840 EVO aside, Samsung simply knows how to make things work!

      In the final analysis, if you want blazing fast speeds from a PCIE based M.2 in the Z97 Deluxe, you MUST use a PCIE x4 adapter board but then that clobbers your high performance graphics lanes if you are trying to use them to their full potential. Asus was pretty sloppy in putting that critical distinction out there.

      If you truly want unbridled x4 performance from a M.2, a X99 or newer board will be required.
      Live and learn…

    • derFunkenstein
    • 5 years ago

    Geoff – I’m looking at the SATA version review and I’m not seeing the same IOMeter graph that you have in here. Is it common that IOPS drops off so hard after ~1 minute? Is it just that Windows is running out of RAM to cache the operations to so the speeds later in the graph are more indicative of drive’s performance and the early results are because of caching? The really high numbers don’t seem to match up with the SATA drive review’s numbers.

      • Dissonance
      • 5 years ago

      The sustained IOMeter results are new, and you’ll be seeing more of them soon. The drop-off is related to the SSD running out of overprovisioned area to accelerate incoming writes. This behavior is normal, though it varies from drive to drive and with changes in the overprovisioned area. More details here: [url<]https://techreport.com/blog/27518/notes-from-tr-next-gen-storage-testing[/url<]

        • derFunkenstein
        • 5 years ago

        Awesome, thanks. I don’t see that I commented on it, so I must not have read it. I’m just full of opinions. lol

    • emorgoch
    • 5 years ago

    Did you guys see the same IO pausing issue with the 1TB model that Anandtech did?
    [url<]http://www.anandtech.com/show/9023/the-samsung-ssd-850-evo-msata-m2-review/2[/url<]

      • Dissonance
      • 5 years ago

      Nope, although we only tested the 250GB M.2 version.

        • continuum
        • 5 years ago

        Any chance of getting a 1TB one in to test?

    • willmore
    • 5 years ago

    Not native PCI-E M.2? *sadpanda*

      • derFunkenstein
      • 5 years ago

      See ClickClick5’s link. The XP941 (and soon, XP951) are those native NVMe implementations.

        • anotherengineer
        • 5 years ago

        But aren’t those for OEM’s only??

          • derFunkenstein
          • 5 years ago

          They’re on Amazon (see the link further down the page). They’re also like $0.80/GB (US) so they’re not cheap.

            • ClickClick5
            • 5 years ago

            I forgot about the XP951. Been waiting so long I forgot! Here is hoping it releases past OEM before Windows 10. The new Haswell-E build will enjoy 2GB/s.

            • derFunkenstein
            • 5 years ago

            Some nerds on MacRumors have gotten them and stuffed them into Nehalem-era Mac Pros (along with Apple-branded/specially keyed PCIe drives), since the adapter cards themselves are pretty cheap. These things are just begging for an updated system like Haswell-E, though.

            • derFunkenstein
            • 5 years ago

            Perhaps of interest to you: PC Perspective is teasing a live stream for tomorrow with Intel regarding NVMe PCI-express solutions for consumers.

            • ClickClick5
            • 5 years ago

            Found some info on the 951, posted here: [url<]https://techreport.com/discussion/28032/a-fresh-look-at-storage-performance-with-pcie-ssds?post=895863[/url<] I'll watch the stream too, thanks!

            • anotherengineer
            • 5 years ago

            Ah US, explains why I have not seen them in Canada.

            Ya nice premium there for sure.

    • ClickClick5
    • 5 years ago

    Well….looks like it will still be this fellow for me on the new build:
    [url<]http://www.amazon.com/Samsung-XP941-256GB-PCIe-MZHPU256HCGL/dp/B00J9V53M6/ref=sr_1_fkmr0_1?ie=UTF8&qid=1427811958&sr=8-1-fkmr0&keywords=250gb+xp941[/url<]

    • nico1982
    • 5 years ago

    Genuine question: does the price difference between form factors covers some insanely greedy licensing fees or it is just the usual cool-factor tax?

      • smilingcrow
      • 5 years ago

      Neither, it’s down to competition and supply and demand.

      • derFunkenstein
      • 5 years ago

      I think it’s an economies of scale thing. As demand for M.2 increases, so will production and price parity will be achieved.

        • nico1982
        • 5 years ago

        I can see what both you and smilingcrow wrote, and I agree that it does play a role. Still, +27% on the 500GB model when the memory chip and the controller are exactly the same, well, it seems a bit absurd.

          • derFunkenstein
          • 5 years ago

          Yeah, it does seem a little high. I actually have an mSATA RAID card (Addonics AD4MSPX2) sitting here that I’d love to jam full of mSATA drives. Can’t bring myself to do it at the current price, though.

          BTW I have no need for such a device, but the card was free and how fun would it be to saturate 4 lanes of PCI-e 2.0 bandwidth? That’s like 2GB/s theoretically.

    • Milo Burke
    • 5 years ago

    Very useful for laptops!

    I’m hoping Chromebook style laptops can be bought OEM with a tiny SSD, update for 1/2 the price aftermarket. And I’m hoping that standard laptops will ship with M.2 standard as well as 2.5″ standard, so users can boot from an SSD and keep media on mechanical storage. Best of both worlds!

    Price is decent, but not great. We can all look forward to some competition in this space. Hopefully the MX-100 or its equivalent will be next.

      • bthylafh
      • 5 years ago

      At least some (I expect most, honestly, because of cost optimization) Chromebooks use eMMC for flash storage instead of one of these. It wouldn’t surprise me if more bottom-end Windows laptops start doing the same, as some do already.

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