Samsung SM951 PCIe M.2 512GB SSD Review

PCMark 8 Advanced Workload Performance

Futuremark created what we consider to be the best SSD benchmark to date. It shows both heavy and light use over time. The advanced disk tests run from a command line interface, preconditioning the drives before simulating heavy workloads. After the steady state heavy workload metrics finish, five-minute intervals fit between each test, allowing the device under test to recover through background activity with garbage collection, TRIM and wear leveling. This simulates typical consumer workloads that we experience everyday. 

Throughput Tests

The three drives on our chart make analysis easy, since performance varies by a wide margin.

Even under heavy workloads, the SM951 512GB is significantly faster than than the other two PCIe-based SSDs we benchmarked.

For most users, the light workload tests better resemble real-world conditions experienced on a daily basis. What surprises us is the large difference between the highest-performing Samsung SM951 and Plextor's last-place M6e Black Edition 512GB.

Latency Tests

Low latency is what makes your computer feel responsive. This is why systems equipped with SSDs are so much faster than those with mechanical disks. Hard drives are bottlenecked by heads and platters moving around, while SSDs can jump to the next transaction without that wait.

This is the first chart in our review where Samsung's latest is beaten by another SSD. The SM951 delivers higher throughput, but at the same time exposes us to higher latency.

The difference between the XP941 and SM951 is so small that it's almost negligible. Both Samsung SSDs deliver lower latencies than a majority of SATA-based drives. Unfortunately, Plextor's M6e Black Edition lands well above the latency levels we expect from a premium SSD in 2015. 

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  • blackmagnum
    This is an awesome upgrade for some Macbook Air/Pro users, but just wait until Intel shows their product... and will there be any hardware compatibility issues with DIY upgrades?
  • Sakkura
    I'm disappointed the promised NVMe support did not materialize. But I guess Samsung is saving that for later retail products. Can't argue with the performance though, this is by far the fastest consumer SSD around.
  • Memory Ever
    May I know the model and nae of the PCIe adapter you used in the tests???
  • JOSHSKORN
    No 1TB edition? Fail.
  • tom10167
    I wish they'd put an 840 or 850 pro in the comparison just to give us a better sense of scale. This drive is incredible, though, and $550 for a 512GB cutting edge drive is not terrible!
  • mapesdhs
    The Power Restricted Performance graph is stupid. Please stopping using
    graphs with origins that don't start at zero - the visual graphic impact is
    totally meaningless.

    Ian.
  • jeffunit
    You might want to fix the labels of your graphs. Latency in seconds? One chart shows a write speed of about 80 gigabytes per second.
  • liquidpower
    I also wished they put a 850 pro in the charts to see the jump from the fastest sata to the PCIe-based M.2
  • maestro0428
    You can purchase these at newegg.com in the Enterprise SSD section. I want one!
  • generalsheep
    Is this little bastard bootable,so i can use it as my maindrive?
  • CyranD
    I have my eye on purchasing a Sager NP8652 in the near future. Currently they list Samsung XP941 as a option. I am hoping before am ready to buy they add the Samsung SM951 as a option.

    Quote:
    Is this little bastard bootable,so i can use it as my maindrive?


    Sager let you set the Samsung XP941 as the boot drive so I assume the SM951 can be used as a boot drive.
  • Blueberries
    I would have liked to see the 850 Pro included in this as well
  • CRamseyer
    I didn't need an adapter to test this product. The ASRock Z97 Extreme6 has a M.2 x4 slot that connects directly to the CPU.

    Yes, this product is bootable. The only modern PCIe SSD that is not bootable is from Fusion-IO.
  • wolfy747400
    Any ideas why this SSD performed a little faster on some tests on a Intel Z68 Express-based motherboard than the Z97?
  • kyuuketsuki
    While the drive's performance is certainly impressive, the serving time graph shows what you really need to know: the performance will make practically no difference in the vast majority of consumer workloads. The only people who should be spending the premium for this drive are professionals who will regularly be transferring large files around. Anyone else is just wasting money, as any modern SSD will perform largely the same in practice, even if their benchmark numbers aren't as impressive.
  • damric
    I am interested in M2 since my motherboard has a slot for one. Do they work as boot drives yet? I haven't been following closely but last time I checked they did not.
  • RamCity
    Quote:
    This is an awesome upgrade for some Macbook Air/Pro users, but just wait until Intel shows their product... and will there be any hardware compatibility issues with DIY upgrades?


    Sadly neither the SM951 or XP941 are compatible upgrades in the MacBook Air or the current cylindrical Mac Pro as the standard M.2 interface connector is different from the one that Apple use. Older Mac Pro towers are fine with the use of a standard PCIe to M.2 adapter card.
  • RamCity
    Quote:
    I am interested in M2 since my motherboard has a slot for one. Do they work as boot drives yet? I haven't been following closely but last time I checked they did not.


    Most 'modern' motherboards with Z97/H97 or X99 chipsets can boot the XP941 and likely the SM951 as well, so long as your bios is up to date. Also, like Chris mentioned in the article, you'll also typically need to install windows from a USB drive.
  • CRamseyer
    Yes, they work as a boot drive.
  • damric
    1901805 said:
    Quote:
    I am interested in M2 since my motherboard has a slot for one. Do they work as boot drives yet? I haven't been following closely but last time I checked they did not.
    Most 'modern' motherboards with Z97/H97 or X99 chipsets can boot the XP941 and likely the SM951 as well, so long as your bios is up to date. Also, like Chris mentioned in the article, you'll also typically need to install windows from a USB drive.


    1888934 said:
    Yes, they work as a boot drive.


    Thanks. I might pick one up for my ASUS Z97I-PLUS.
  • bit_user
    *yawn* I just clicked for some tasty NVMe benchmarks. Should have mentioned it's AHCI-only, sooner.
  • hst101rox
    4K random reads/writes aren't any better than SATA 3 SSDs so as an OS drive I don't see an advantage. For mass storage/large files, sure.
  • CRamseyer
    This drive has the highest 4K QD1 random read from a consumer SSD available today, over 12K IOPS. It has the highest QD2 and QD4 as well. Most of us will never get beyond QD8 under normal use. The 4K random writes are really good too.

    A better metric to look at is on page 4, the mixed workload tests. You will never just read or just write data with an OS drive.
  • Markor
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