A 1400 MB/s SSD: ASRock's Z97 Extreme6 And Samsung's XP941

Results: A PCIe SSD's Sequential Performance

Samsung's 512 GB XP941 is the first four-lane PCI Express M.2 drive in our lab, and we want to know how it performs. In order to figure out what the SSD is capable of, we'll mix up some of the tests from our other storage reviews. First, we benchmark it in ASRock's Ultra slot, which won't limit the device's peak throughput. Then we compare those results to the PCH-attached M.2 slot, which I expect will artificially cap its potential. 

Sequential reads and writes are most likely to illustrate my point, so we start there.

Sequential Reads

If you read the previous page, then you won't be surprised by an outcome of 1250 MiB/s in the M.2 slot attached to our Haswell-based Core i5-4670K. A conversion to decimal lands us right around 1.4 GB/s.

Swap the drive over to a PCH-attached M.2 slot, though, and the binary read throughput drops precipitously. Eight-hundred megabytes per second is nothing to sneeze at. But that's still 33% less than the result measured from ASRock's Ultra slot.

Now check out Samsung's otherwise well-reviewed 840 Pro. It looks shabby in comparison, even though we know it to be one of the best SATA 6Gb/s options available. Then again, there's more to the performance story than just sequential throughput.

Sequential Writes

Sequential writes are even more illustrative of the puissant ASRock Z97 Extreme6/Samsung XP941 combo.

And here's why. The 840 Pro gives us almost 450 MB/s of peak bandwidth (again, in binary). Samsung's XP941 in the PCH-attached, two-lane M.2 slot offers a substantial increase, appearing just under 800 MB/s. The SSD should be commended; it can fully exploit a pair of PCI Express lanes, which SanDisk's A110 and Plextor's M6e cannot do.

Then the XP941 jumps up a notch by peaking in excess of 1000 MB/s when we drop it onto ASRock's CPU-attached Ultra M.2 four-lane slot. That's basically what two of the fastest 6 Gb/s SATA drives achieve in RAID 0.

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  • aminebouhafs
    Once an SSD in plugged into the Ultra M.2 slot, the bandwidth between central processing unit and graphics processing unit is cut-down by half. Therefore, while the end-user gets additional SSD performance, the end-user may lose some GPU performance because of insufficient bandwidth between it and the CPU.
    -8
  • JoeArchitect
    Very interesting article and a great read. Thanks, Chris - I hope to see more like this soon!
    8
  • wussupi83
    great article! - although z97 still seems boring
    0
  • Eggz
    This makes me excited for X99! With 40 (or more) lanes, of PCI-e (probably more), there will be no need to compromise. We have to remember that the Z97 Chipset is a consumer-grade product, so there almost has to be tradoffs in order to justify stepping up to a high-end platform.

    That said, I feel like X99, NVMe, and and M.2 products will coincide nicely with their respective releases dates. Another interesting piece to the puzzle will be DDR4. Will the new storage technology and next-generation CPUs utilize it's speed, or like DD3, will it take several generations for other technologies to catch up to RAM speeds? This is quite an interesting time :)
    -1
  • Amdlova
    Chris test the asrock z97 itx... and another thing... my last 3 motherboard from asrock and i want to say Asrock Rock's!
    5
  • Damn_Rookie
    While storage isn't the most important area of computer hardware for me, I always enjoy reading Christopher's articles. Very well written, detail orientated, and above all else, interesting. Thanks!
    0
  • hotwire_downunder
    ASRock has come along way, I used them a long time back with disappointing results, but I have started to use them again and have not been disappointed this time around.

    Way to turn things around ASRock! Cheap as chips and rock steady!
    0
  • alidan
    @aminebouhafs if i remember right, didn't toms show how much performance loss there is when you tape gpu cards to emulate having half or even a quarter of the bandwidth? if i remember right back than the difference was only about 12% from 16 lanes down to either 4 or 8
    0
  • Eggz
    Anonymous said:
    @aminebouhafs if i remember right, didn't toms show how much performance loss there is when you tape gpu cards to emulate having half or even a quarter of the bandwidth? if i remember right back than the difference was only about 12% from 16 lanes down to either 4 or 8


    PCI-e 3.0 x8 has enough bandwidth for any single card. The only downside to using PCI-e lanes on the SSD applies only to people who want to use multiple GPUs.

    Still, though, this is just the mid-range platform anyway. People looking for lots of expansion end up buying the X chipsets rather than the Z chipsets because of the greater expandability. I feel like the complaint is really misplaced for Z chipsets, since they only have 16 PCI-e lanes to begin with.
    1
  • cryan
    Quote:
    Once an SSD in plugged into the Ultra M.2 slot, the bandwidth between central processing unit and graphics processing unit is cut-down by half. Therefore, while the end-user gets additional SSD performance, the end-user may lose some GPU performance because of insufficient bandwidth between it and the CPU.


    Well, it'll definitely negate some GPU configurations, same as any PCIe add-in over the CPU's lanes. With so few lanes to work with on Intel's mainstream platforms, butting heads is inevitable.

    Regards,
    Christopher Ryan
    2
  • cryan
    Quote:
    While storage isn't the most important area of computer hardware for me, I always enjoy reading Christopher's articles. Very well written, detail orientated, and above all else, interesting. Thanks!


    Awww, shucks!

    Regards,
    Christopher Ryan
    3
  • obamaliar
    Supercool review, Just as a note though any pair of good SATA Based SSD's will blow the doors off of that x941. For example I am getting 740.00MB/s bandwidth at steady 5 and 948.37MB/s at recovery 5 for PCM8 extended photoshop heavy from a pair of Intel 730's
    -1
  • obamaliar
    Supercool review, Just as a note though any pair of good SATA Based SSD's will blow the doors off of that x941. For example I am getting 740.00MB/s bandwidth at steady 5 and 948.37MB/s at recovery 5 for PCM8 extended photoshop heavy from a pair of Intel 730's
    -1
  • Evolution2001
    obamaliar, how do you reckon that your 740MBps or 948MBps is faster than 1400MBps? (referencing the sequential read of the tested drive)
    SATA3 has a theoretical max of 6Gbps (750MBps). However, the practical max is more around 600MBps.
    Assuming you are running your Intel 730's in RAID-0 and achieving the max practical throughput, you'd still only come up with ~1200MBps which is slower than what Tom's saw at 1400MBps ON A SINGLE DRIVE.
    1
  • obamaliar
    Quote:
    obamaliar, how do you reckon that your 740MBps or 948MBps is faster than 1400MBps? (referencing the sequential read of the tested drive)
    SATA3 has a theoretical max of 6Gbps (750MBps). However, the practical max is more around 600MBps.
    Assuming you are running your Intel 730's in RAID-0 and achieving the max practical throughput, you'd still only come up with ~1200MBps which is slower than what Tom's saw at 1400MBps ON A SINGLE DRIVE.

    Quote:
    obamaliar, how do you reckon that your 740MBps or 948MBps is faster than 1400MBps? (referencing the sequential read of the tested drive)
    SATA3 has a theoretical max of 6Gbps (750MBps). However, the practical max is more around 600MBps.
    Assuming you are running your Intel 730's in RAID-0 and achieving the max practical throughput, you'd still only come up with ~1200MBps which is slower than what Tom's saw at 1400MBps ON A SINGLE DRIVE.
    Evolution 2001, I am referring to OS simulated performance IE CRYAN's PCMark 8 extended testing. Please read the article and you would understand that sequential performance is really a non-factor in comparison to random performance in an OS environment. Right now, SATA RAID has vastly superior random performance to PCIe drives like the X941, even if you were to soft RAID a pair of X941's together they cannot match a pair of good SATA SSD's in RAID in an OS environment. I cannot show you that exactly because Soft RAID is not bootable. look here: https://www.facebook.com/groups/1445011539065390/ there ia a pair of X941's soft raided getting their asses kicked by SATA RAID. The reason? 4K writes do not scale on PCIe drives. When PCIe drives can be RAIDed, bootable in RAID and have an RST type driver that allows for write caching Then they will become the superior OS disk.
    -1
  • cryan
    Anonymous said:
    Quote:
    obamaliar, how do you reckon that your 740MBps or 948MBps is faster than 1400MBps? (referencing the sequential read of the tested drive)
    SATA3 has a theoretical max of 6Gbps (750MBps). However, the practical max is more around 600MBps.
    Assuming you are running your Intel 730's in RAID-0 and achieving the max practical throughput, you'd still only come up with ~1200MBps which is slower than what Tom's saw at 1400MBps ON A SINGLE DRIVE.

    Quote:
    obamaliar, how do you reckon that your 740MBps or 948MBps is faster than 1400MBps? (referencing the sequential read of the tested drive)
    SATA3 has a theoretical max of 6Gbps (750MBps). However, the practical max is more around 600MBps.
    Assuming you are running your Intel 730's in RAID-0 and achieving the max practical throughput, you'd still only come up with ~1200MBps which is slower than what Tom's saw at 1400MBps ON A SINGLE DRIVE.
    Evolution 2001, I am referring to OS simulated performance IE CRYAN's PCMark 8 extended testing. Please read the article and you would understand that sequential performance is really a non-factor in comparison to random performance in an OS environment. Right now, SATA RAID has vastly superior random performance to PCIe drives like the X941, even if you were to soft RAID a pair of X941's together they cannot match a pair of good SATA SSD's in RAID in an OS environment. I cannot show you that exactly because Soft RAID is not bootable. look here: https://www.facebook.com/groups/1445011539065390/ there ia a pair of X941's soft raided getting their asses kicked by SATA RAID. The reason? 4K writes do not scale on PCIe drives. When PCIe drives can be RAIDed, bootable in RAID and have an RST type driver that allows for write caching Then they will become the superior OS disk.


    Actually, the 4 KB writes are really an artifact of the AHCI controller/API. If you took the same flash and controller on the Sammy, but rigged it to use NVMe, I think you'd see a big bump in random 4 KB performance. I've said over and over that desktop users, for now, are better off by using a couple SATA drives in RAID. More than just adding bandwidth, which isn't always important (strictly speaking), it lowers service times significantly. Plus, it's great to just keep adding cheap drives and getting more performance and capacity (when striped). See the Plextor M6e PCIe review for my thoughts on this.

    It's all academic anyway, since you can only buy the XP941 from a few random places, and it's $750. If I had a laptop which could use it, maybe I go that route, but even there SATA is just more power efficient. Give me a 1 TB EVO or M550 instead..... at least for the time being.

    PS: Is this Jon C??

    Regards,
    Christopher Ryan
    2
  • obamaliar
    Thanks for the reply love your stuff C Ryan :)
    0
  • Eggz
    Anonymous said:
    Give me [either a 750 GB] or a 1 TB EVO or M550 instead..... at least for the time being.


    Totally agree! For now.

    I also added the 750 EVO in there because (I believe) the only difference between the 1TB and the 750GB is capacity, unlike the smaller drives, which actually have less performance (i.e. 120, 250, & 500 GB).
    1
  • logainofhades
    I would rather use a single powerful GPU anyway, so the cut to 8x due to the ultra M.2 slot doesn't bother me at all. This is definitely and interesting board. I want an Ultra M.2 slot on a mini-itx board. :D
    0
  • lukebutters
    If the RAID controller is set up with 4 disks in RAID 10, will the DMI limit be reached?
    0