8 PCIe & SATA M.2 SSDs Test ASRock’s Fatal1ty 990FX Killer AM3+ AMD MotherBoard


ATTO Disk Benchmark is perhaps one of the oldest benchmarks going and is definitely the main staple for manufacturer performance specifications. ATTO uses RAW or compressible data and, for our benchmarks, we use a set length of 256mb and test both the read and write performance of various transfer sizes ranging from 0.5 to 8192kb. Manufacturers prefer this method of testing as it deals with raw (compressible) data rather than random (includes incompressible data) which, although more realistic, results in lower performance results.

ATTO Chart

Right off, it was great to see that the Samsung XP941 was recognized and we believed it might yield the highest benchmark results, considering what it is capable of in X4 mode.  Unfortunately, it topped out at 821MB/s, a speed well below the 10Gbps ceiling and we had to wonder if this was going to be the highest we would see in PCIe 2.0 X2 performance.

Samsung XP941 512GB PCIe X4 M.2 SSDin ASRock FX990 Killer Mobo M.2


Crystal Disk Benchmark is used to measure read and write performance through sampling of highly compressible data (oFill/1Fill), or random data which is, for the most part, incompressible.

Crystal Chart

In examining the Crystal DiskMark write performance of the SATA SSDs, we could confirm the typical AMD SATA performance deficiency that has always been present when one compares these speeds to  typical Intel based SSD performance.

Toshiba HG5d 512GB SATA M.2 SSD in ASRock FX990 Killer Mobo

We would like to identify whether AMD also affects PCIe performance in some way but but there really isn’t enough data just yet. The only true sample we can look at is the Plextor/Lite-On M6e 256GB PCIe X2 M.2 SSD and it is not really a fair comparison as, last we tested it, it boot into its own BIOS prior to testing, whereas now, it boot into the 990FX BIOS which surprised us.  As well, performance is a bit less but this drive has undergone significant use prior.  Although CDM results appear to be a bit lower, ATTO results are still dead on.

Plextor M6e 256GB PCIe X2 M.2 SSD in ASRock FX990 Killer Mobo


  1. awesome review Les – can you confirm that you were able to boot the Samsung XP941 in this motherboard? It looks like that IS what you did, but just wanted to be sure….

  2. or german review ?

  3. Hope to see PCIe X4 M.2 on the upcoming Intel chipset series 9!

  4. Could I put 5 r9 cards ? How much watts is needed ?

  5. It’s interesting that the Samsung XP941 PCIe x4 SSD worked in this motherboard, despite the M.2 socket only supporting PCIe x2. We’ve had zero success with installing the XP941 in the ASUS Maximus VI Impact mobo, which also has dual support for PCIe x2 M.2 / SATA M.2. I wonder what they’ve done different in the Asrock board that they haven’t in the ASUS board?

    • The implementation used in this first ASUS release is poor and will only support a single lane, not a four lane design such as the XP941….and then also, not as a boot device. The 990FX Killer, on the other hand, will support the XP941 and as a bootable drive, whereas initially it would not. We worked with ASRock to achieve such.

  6. With two graphic cards, does it run at (x16/x16)?

    • WE haven’t the cards to test such sorry but specs point out that it should.

    • This is dependent on the processor, as an 8 core FX CPU (eg. FX 8350) will support 38pcie lanes, but others will not.

      • Not true. Unlike Intel based systems, in which the number of available PCIe lanes are dependant on the CPU, in AMD based machines the number of available PCIe lanes are based entirely on the onboard controller (ie: the number of PCIe lanes are determined by the motherboard, NOT the cpu for AMD based machines). So really it doesn’t matter how many cores you have.

    • If it is running 3x @ x8/x8/x4, then it is doubtful it can do 2x @ x16/x16.
      It even shows that the “quad SLI” is only 2x @ 8x/8x (obviously using two dual GPU cards).

      • from what i have read, it supports PCIE2.0 @ X16X16X4 with use of the Molex plug on the bottom of the motherboard for power stabilization to be used with 2 or more gpu’s

  7. Hi Les, just did a new build. ASrock990FXKiller, FX8320 3.5Ghz, 16G G.Skill Trident X DDR3-2400 PC3-19200, 2×8 , HD 7850 graphics powered with 600 w Thermallake.
    Dead on post! Unhooked everything but both 12v connectors and jumped the ps posts, worked, started adding one thing at a time allowing time for post then shutting down to add one more thing. I am on it now, but it does not run like it should and not been able to run B2 memory slot. Any ideas?

    • Jut had that same problem when moving the Intel system over to the new build…Turns out the retaining screw on the bottom of the mobo was off ever so slightly creating indirect pressure from the cooler to the cpu. That was the exact result… Read the new posted article on the new build…P.2

  8. 1 x Ultra M.2 Socket (M2_1), supports M.2 PCI Express module up to Gen3 x4 (32 Gb/s)

  9. cannot find a straight answer to this: PCIe card (with m.2 SSD, like Plextor’s m6e) or straight m.2 SSD (like Crucial’s M500 m.2 SSD)? which one would be faster?

    • We have several reports that explain this. The Plextore M6e is a native PCIe M.2 SSD that uses 2 PCIe lanes while the M500 M.2 is a SATA based M.2 PCIE SSD and does not take full advantage of PCIe.

      Right now we have SATA M.2 (550MB/s), PCIe x2 M.2 (800MB/s) and PCIe X4 M.2 (1.2GB/S).

      The Plextor is faser, although in the new ASRock board, the Samsung XP941 is higher yet.

      • Thanks, I guess Plextor it is then.
        I cannot really justify paying 4 times as much for the Samsung XP 🙂

  10. How does this mobo compare to Asus M5A99X Evo R2.0? My local pc store is trying sell me it instead of the Asrock for the same price?

  11. Erwin Thierry Klein Haneveld

    The answer to the memory issues is simple , the AMD FX Cpu does not support any higher speed than 1866Mhz, if you want to go higher then you need to install 1 dimm per channel not 2 that wil not work!

    check the memory builders site for compatibilty. they only tell you can use 16GB as in 2x 8GB but Asrock should tell you to insert the memory in the firts bank of channel 1 and fist bank of channel 2! not both in same channel!,

    see this:


    as any AMD FX processor has an memory issue. and that is only supports memory up to 1866Mhz! not higher!

    see section Features!

    there you will find this info:

    Integrated DRAM Controller with AMD Memory Optimizer Technology

    A high-bandwidth, low-latency integrated memory controller

    Supports up to DDR3-1866

    see that gskill tells you the max of 16GB
    only at 1600mhz you can use 4x8GB of ram!

    • i do not mean to cause an argument but, i have 2x8GB Team Xtreem (white) rams clocked at 2400 10cas, and i have them stable at close to 2133mhz on my 990FX killer fatal1ty mobo with an fx-6300, mind you im not the smartest overclocker, but it is very stable doing what i want it to do, game, record, video edit and upload to youtube! https://valid.x86.fr/bmkvlq

      i don’t usually run testing software because i am lazy, that lazy infact i don’t even turn my computer off, it has been stable as for 3 weeks nonstop!

      only reason i opted for such high speed ram, 1: read on many forums that fx’s can handle 2133mhz, 2: read up its cheaper buying 2400mhz ram and underclocking it to suit, 3: researched 2 and found this to be true on pricing, heck i live in Australia it was cheaper to get 2400Mhz from Newegg australia (thats actually in America) than it is to get 2133/2400 mhz in Australia!

      i am very happy with it, granted, i don’t even use half my ram but meh, it was cheap and it works, “I’m a happy little Vegemite!”

      • yep i also have 2 ddr 3 2133 mhz ram modules that will happily run at ddr 3 2400 mhz on my 8320 e msi 970 gaming setup while the amd fx officially supports ddr3 1866 just like all the intels except for the new one it can take up to even ddr3 3000mhz so long as the board can handle it and your willing to overclock the nb to utilize the bandwidth

  12. Is this model support plextor PX-G128M6e?
    I cannot see from the list.

  13. Samsung XP941 PCIe X4 M.2 SSD for work in boot mode you must go [f11] with an usb/boot/win and select UEFI (usb storage) installing win7/8

    I’ve used
    for make my usb win setup, now xp941 work correctly booting.

  14. Francis Nacional

    How about running these m.2’s on pcie adapter cards? I have seen a few of these on ebay relatively cheap and they claim to be bootable with an m-key m.2. I would like to know if it is worth the money for those of us who don’t have the latest Intel boards and this AsRock…

  15. Will the new Samsung XP951 M.2 SSD run on the motherboard?

    • We cannot answer that as we havent the board for testing any longer. If it is the AHCI version, however, there shouldn’t be any problem whatsoever. NVMe may be a different animal on older boards.

      • Thanks, I’m going to pick it up and buyers protection so if it doesn’t work I can return it no questions asked.

  16. From what I’ve seen, m.2 drives can get extremely hot….what temps were achieved during these tests?

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