Samsung SM951 NVMe M.2 PCIe SSD Review

Legit Reviews Reviews Samsung SM951 NVMe M.2 PCIe SSD Review

Posted by Nathan Kirsch | Fri, May 01, 2015 - 12:16 PM

23 Comments

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Samsung SM951 NVMe Final Thoughts and Conclusions

The Samsung SM951 NVMe was found to be an impressive M.2 SSD, but NVMe is very new not for everyone. For starters you have to have a motherboard that features a UEFI BIOS that supports NVMe. Then you have to jump through some hoops to get Windows installed as the Samsung XP941 and SM951 SSDs don’t have an OPROM, so you can’t just toss in the Windows installation disc of USB drive and go. You have to use a program like RUFUS to install Windows on the drive in EFI mode. Rod over at RAM City has a guide on how to setup Windows on a Samsung XP941 or SM951 that you can check out here.

Once you get the drive up and running you’ll have to use the Microsoft NVMe driver as Samsung doesn’t have their own driver. You’ll also find out that Samsung offers zero customer support for the SM951 NVMe drive since it’s an OEM only device and running something simple like secure erase could be a total PITA unless you wanted to run Linux and perform the operation on another system. To top all that off there is the whole Force Unit Access (FUA) issue that is entirely new to us and many in the industry. The Intel NVMe drives aren’t impacted by FUA’s and since this is the only other NVMe drive that we have to test! We aren’t sure what the overall impact will be for enthusiasts using this drive with the Microsoft Windows 8.1 NVMe driver, but you can flip through our benchmark pages with this drive being tested as a secondary storage device and quickly see the write performance is nothing to write home about!

The Sasmsung SM951 AHCI drives might be better for those that are looking for something without so many complexities! You can also find them online today in-stock and buy one!

Samsung SM951 M.2 PCIe SSD Drives
Part Number	Capacity and Features	Sequential (R/W)	Max 4K IOPS (R/W)	Price
MZ-HPV128	M.2 Form Factor 128GB	2000/600 MB/s	90k/70k IOPS	$159.99
MZ-HPV256	M.2 Form Factor 256GB	2150/1200 MB/s	90k/70k IOPS	$264.95
MZ-HPV512	M.2 Form Factor 512GB	2150/1500 MB/s	90k/70K IOPS	$499.95

Legit Bottom Line: The Samsung SM951 NVMe looks promising, but it is complicated and it might be a good thing that it isn’t readily available on the market just yet!

Questions or Comments? View this thread in our forums!

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NexxtBs

@MikeO55:disqus Thank you so much, my writing speed with my PM951-Drive in my XPS 15 9550 was really terrible, and thanks to you I tried downloading the NVMe 950 Driver and now the computer flies, I really mean it, is so much faster. Everyone else try it with the NVMe Driver here: http://www.samsung.com/global/business/semiconductor/minisite/SSD/global/html/support/downloads.html
Michael Owen

Noticed that PCMark 8 was on special offer on STEAM (80% off) so purchased it and then ran it against the SM951. Was initially a bit disappointed to see that the results were very similar to those initially.
IE. Storage Score: 4437 & Bandwidth 102.97 MB/s

So out of interest I re-installed the NVMe driver for the Samsung 950 pro and got:

[URL=http://s198.photobucket.com/user/mikedowen/media/PCMark%208%20Samsung%20NVMe%20driver_zpsp4wqahq9.jpg.html][IMG]http://i198.photobucket.com/albums/aa200/mikedowen/PCMark%208%20Samsung%20NVMe%20driver_zpsp4wqahq9.jpg[/IMG][/URL]

So looks like running with the Samsung driver is the way to go.
Michael Owen

Here is a run of AS SSD. Looks just fine to me.
Michael Owen

Since the firmware update in July, the FUA “issue” is now a non issue.
The problem that legit experienced while running AS SSD is because they must have installed it somewhere other than on the C: drive. If you do this then while the read side of the app will work, the write side wont (it just hangs). Somewhat stunned that they did not realize this! I fell for this one myself once, as my download folder is on another internal drive, so without thinking… I unpacked the cab and installed it here. Low and behold, I had the same problem as Legit. Install it on the C: drive and it ran just fine. All metrics as expected. If you don’t believe me, try it.

I have been running one of these drives now on a Skylake platform as a boot drive for some 4 months now and it absolutely flies. Boots to a usable desktop in 13 seconds flat! Though I suspect Windows hybrid shutdown and MSI fast boot help a bit as well. No problems at all and all test show it fairly races along.

Just downloading the latest version of PCMark and I’ll post the results up when ready.

Only real downside to this drive, is that it is truly an OEM system product (not really meant to be sold to the general public) so little (read none here) support from Samsung. As such, most home PC enthusiasts are probably better off getting the Samsung 950 pro, as this is a retail product.
- James Lloyd
  
  Dear Michael, could you please let me know where/how you downloaded and installed this firmware update. I can’t find any resources on the SM951 NVME other than some guides on physical installation.
  - Michael Owen
    
    Hi.. you can’t update the firmware on these drives unluckily. It’s just that mine is one of the later drives and came with the latest firmware mentioned in the Legit review.
    
    Again unluckily, you wont find much (read pretty much “any” ) support for these drives. As they are OEM system builder parts and not really intended to be sold directly to retail customers. No way to read the SMART data, no way to update the firmware, warranty resides with the re-seller (IE. not Samsung), no retail packaging etc. etc.
    O/L shops really should be aware of this and highlight the fact in their advertising etc.
    
    The consumer version of this (IE. retail version), is the Samsung 950 pro. Which is fully supported by Samsung.
    
    Not much help to you I know. But people need to be aware when buying true “bare bone” parts like this, what is really involved.
    
    PS. Not run PCMark, as I would need to purchase the full version to get the storage test and it’s not worth it. But Legit has now updated their review, showing that the FUA issue has been resolved by a later firmware update.
    - Michael Owen
      
      Maybe worth mentioning that the NVMe driver fo the Samsung 950 pro will also install and work for the SM951. So if anyone is still having problems, then this might be worth a shot. I tried it… but it did not seem to make any difference in the performance. So I reverted back to the native Windows 10 NVMe driver. Which in my case at least, appears to work just fine.
darren evans

so that’s it?? People like me with this crap have to just deal with it? It performs terribly. Boot times are horrendous. Far slower than my previous 850 pro
Minkyu Kim

If you finding a tool to get SMART with Samsung NVMe devices, Naraeon NVMe Tools can be reasonable option.
http://naraeon.net/en/latest-nvme-tools
Acer_Predator

Guys I have purchased this crap ssd and speeds are even worse than AHCI !
SizLion

Anyway you can share what the original and new firmware revisions were?
- Carenotbutpleasefeelfreetotrol
  
  Sorry I could not say, but I can say that mine have got BXW7 and drive have got the date July 7 – 2015 on it so not very old.
  - Lukadlo
    
    Just bought this SSD (SN starts the same BXW7300Q 2015.09) and I must say, that I face the same issue. The PCmark8 and AS SSD show terrible write speeds. Other benchmarks like ATTO show correct speeds..
Christopher Caruk

Hello, I’ve just been comparing a 512GB 951 NVMe variant that I purchased yesterday with an existing 512GB 951 AHCI. Apparently it’s a sample rather than a production unit but I’m seeing fantastic read speeds but horrific write speeds. In my case I’m using with an Asus Z97i-plus with the latest BIOS. The board identifies the 951 and allows me to install windows (8.1 all latest updates)… so far so good. Unfortunately when I run speed tests against the NVMe variant I get 10 times slower write speeds compared to the AHCI 951.

CrystalDiskMark: AHCI variant (connected to PCIe 3.0 bus)

Seq Q32T1 – 1172MB/s read | 1043MB/s write
4k Q32T1 – 398MB/s read | 289MB/s write
Seq – 1052MB/s read | 900MB/s write
4k – 35MB/s write | 128MB/s write

CrystalDiskMark: NVMe variant (connected to PCIe 3.0 bus)

Seq Q32T1 – 2264MB/s read | 501MB/s write
4k Q32T1 – 563 MB/s read | 21 MB/s write
Seq – 1299 MB/s read | 170 MB/s write
4k – 54 MB/s read | 0.98 MB/s write

Blindingly fast read but horrifically slow write speeds.

I’ve also tested using the Z97i-plus’s M.2 slot. I see reduced read speeds due to the limited, 10Gbps, speed of the M.2 on this board but the same horrific write speeds.

Is there something that I might be doing wrong? Could this be a BIOS problem? A Windows NVMe driver problem?

Also… I’ve never been able to match the the read speeds that you posted but I’m seeing a maximum of around 1100MB/s read speed on the AHCI variant.

Could this be a limitation of the board or a misconfiguration of the PCI bus?
theUnhandledException

Ouch. I had been holding off on SM951 AHCI to see what the NVMe version could do. The “FUA/driver/write performance” debacles is disappointing but to be expected given how new it is. NVMe is obviously the way forward but in the interim I may grab a 256GB AHCI version and wait to see how the M.2 NVMe space develops. Thank for this review. I would have been annoyed to discover this issue after the fact. I also think it was shady for Samsung to only report the 4K read numbers (because they KNEW the write number were horrible).
Erwin Thierry Klein Haneveld

its because the NVME by samsung is an oem device so its upto the oem retailer to make the driver for it!
- Nathan Kirsch
  
  That is correct when it comes to utilities that run say the TRIM command, but for an actual Windows NVMe driver that would fall on Samsung!
JayFiveAlive

At least the Intel 750 NVMe SSD has drivers… Samsung will never have drivers? From the way people were talking the 951 NVMe was supposed to be a fair bit better than the 750.
- Nathan Kirsch
  
  Samsung obviously doesn’t have a drive for the SM951 NVMe, but they are looking into it. I wouldn’t be surprised that the next NVMe drive by Samsung has a driver set.
TAS

How were you able to verify that the commands issued by the OS resulted in CMD1.CDW12.FUA being set to 1? (per the NVM Express specification)
Or is that a hypothesis that the Microsoft NVMe driver sets the FUA bit on all writes?
Disabling write caching implicitly through FUA would be quite disastrous to the performance of so many NVMe devices that it’s hard to imagine Microsoft would make such a change.
- Nathan Kirsch
  
  Samsung themselves gave me the data with FUA enabled and disabled, so I am fairly confident that they know what they are doing!
TAS

AS SSD uses FILE_FLAG_NO_BUFFERING. That’s why the writes are so low. Caching is disabled by the benchmark, by design. The website for AS SSD states this.
FXi2

Too many risks and lack of support for the gains.