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Just got some Intel PMM SSDs - 10x faster than NVMe

Discussion in 'Storage & Backup' started by wwwww, Jul 3, 2020.

  1. wwwww

    wwwww Member

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    Just got these two bad boys:

    [​IMG]

    Before you move this to the memory thread, yes these are SSDs that slot in DDR4 slots based on Intel's 3D XPoint Flash.

    [​IMG]

    Single disk performance is the same so they're being held back by the software or other hardware. That's still nearly 10x the QD1 reads of the best NVMe and more than double the writes.

    My mobo can't boot from them but Intel seems to indicate they'll be bootable in the future and targeted at desktops:
    https://www.legitreviews.com/intel-optane-dc-persistent-memory-coming-to-desktop-workstations_214370

    Oh and these are cacheless numbers, to put things into perspective, this is a cacheless Samsung MLC NVMe disk:
    [​IMG]

    This Intel SSD gets 38x the high QD IOPS and 200x the QD=1 IOPS writes and 5x and 15x for the reads respectively.
     
    Nethiuz and illdrift like this.
  2. luke o

    luke o Member

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    Hmmm. Want.
     
  3. kogi

    kogi Member

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    me 2

    but $1k for 128gb, eep
     
  4. OP
    OP
    wwwww

    wwwww Member

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  5. kogi

    kogi Member

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  6. OP
    OP
    wwwww

    wwwww Member

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    I got them from eBay USA, I just offered USD 240 each. Was AUD 860 shipped for 2 sticks.

    Need a lot of support, that's why they're so cheap on the secondary market because most systems won't run them.

    You need Cascade Lake or Cooper Lake Gold/Platinum or Silver 4215 CPU.
    You also need BIOS support which is very limited at this stage. There is nothing else physical on the motherboard needed for support so support can be added later.

    I'm running these on a Lenovo P720 workstation which is older than these DCPMMs and support was just added with a BIOS update.

    You need to configure them in the BIOS (you can use them as slow RAM as well), but once configured they appear as a block device in Windows 10. Automatically detected, no driver installs needed.

    Windows reports them as RAM that's been reserved by the system.

    [​IMG]

    They don't appear under disk drives though, they come up as Persistent Memory Disks.

    They work in Storage Spaces and are supported. The only limitation I've found within Windows so far is that you can't convert them to Dynamic disks which is deprecated anyway.
     
    Mickatroid and kogi like this.
  7. OP
    OP
    wwwww

    wwwww Member

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    [​IMG]

    This is a single stick without interleaving.

    Threaded writes seem to be the only thing that benefits from interleaving.

    It is clear though that these are capable of so much more but are limited by the software/drivers. With interleaving they bench up to 26GB/s reads on Crystal disk mark with tweaked settings. Reads scale almost linearly with threads and I'm limited to 22 cores per socket.

    Representing them as a block device is done solely for compatibility purposes, Intel calls this 'very slow'. AppDirect mode allows them to be represented as another type of hardware which software interacts with directly without the limitations of block access.
     
  8. Jaco

    Jaco Member

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    So these're sitting in your regular memory slots, show up as formattable media within Disk Management and can retain data even when rebooted? It sounds and speedtests like an ordinary ramdisk but if it manages to have the proper chips on it to act like a disk then that's not bad

    Nice gold processor by the way
     
  9. OP
    OP
    wwwww

    wwwww Member

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    Yes. PMM is persistent memory module. You can mount them as a disk, use them in storage spaces, etc. You will even be able to boot from them soon.

    The chips are Intel's 3d XPoint flash - same as you get in Optane SSDs except a faster controller. They're not volatile RAM chips, so while reads are fast like a RAMdisk, the data stays after reboot. Writes are still slower than DRAM.
     
    Jaco likes this.
  10. Skitza

    Skitza Member

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    The write speed seems quite poor, or is it just me? 3gig read but 1 gig write? Ive seen better stats on the standard nvme samsungs. I'm missing something.... I'd love to add these to our Cisco hosts though don't get me wrong ;)
     
  11. mtma

    mtma Member

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    Cache vs no cache.

    The Samsungs are writing the initial data to the high speed cache and which then the controller works to move away to the actual storage, which in wwwww's example shows is actually only 350MB/s.

    For desktop use cases it's generally sufficient because the SSD's high speed cache is pretty big. But say if you needed a monstrous database or a thrash drive, where you're trading data at the highest speed for long amounts of time as if it was a huge slab of RAM, the slowdown will become apparent. That's where this kind of storage device can strut its stuff.

    Also in this form factor it's fast at small parallel writes too (vs optane SSD)
     
    Last edited: Aug 1, 2020 at 11:51 PM
    wwwww likes this.
  12. hippyhippy

    hippyhippy Member

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    No actual benefit in real world...
     
  13. NSanity

    NSanity Member

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    Quality comment.

    All those storage, database and HPC guys aren't getting benefit ever.
     
  14. Matthew kane

    Matthew kane Member

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    So what are you going to be using these for that will 1. see a benefit for what you're doing, 2. see a substantial improvement over what you currently using and will be using it for?
     

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