easiest and cheapest PCIe SSD for cMP

Discussion in 'Mac Pro' started by barmann, Mar 26, 2018.

  1. barmann macrumors 6502a

    Joined:
    Oct 25, 2010
    Location:
    Germany
    #1
    For my MP 5.1 i'll need to add some fast hard drive space .
    It's got a bunch of drives inside already, so I'm looking at SSDs connected via PCIe cards , to gain some performance, too .

    I did some research , got a bit confused, but it seems to come down to this : most regular SATAIII based SSD m.2 blades like the Samsung 860 EVO use the required AHCI protokol .

    The are not the fastest offerings at 500ish read/write, but will at least support boot and plug into a number of cheap PCIe adapters like the Lycom DT 120/125 etc ..

    PCIe adapters for 2.5" SSds by OWC, Sonnett etc. are far more expensive than the adapters for m.2 blades, while the SSDs themselfes cost the same for 2.5" and m.2 form faktor .

    Faster solutions not limited by SATA, ACHI SSDs like some Kingstons and Samsung 951 models, are becoming rare and demand a premium .

    So, am I right to assume that the easiest and cheapest way to add a (full SATA / 2x drive bay speed) SSD to my MP 5.1, will be something like an Evo 860 m.2 with a Lycom PCIe adapter ?
     
  2. h9826790 macrumors G4

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #2
    It seems you misunderstand something.

    DT-120 only work for AHCI or NVMe PCIe SSD, not SATA SSD

    DT-125 has two SATA SSD slot, which is just to accommodate the m.2 SSD. There is no SATA controller onboard. You will need another PCIe SATA III card (or connect the cables back to the native SATA II ports) to make the SSD works.
     
  3. kschendel macrumors 65816

    Joined:
    Dec 9, 2014
    #3
    If you're running High Sierra (or linux) you can use NVMe SSD's with inexpensive controller-less M.2 cards like the DT-120 or equivalent. You can't boot from them though, not on a cMP as far as I know.

    You can also beat the Samsung price by a good bit if you aren't worried about getting the top tier performance, which you're likely to only see in special circumstances anyway.

    Don't confuse form factor and interface. m.2 is a form factor. m.2 form cards can have either SATA or PCIe interface, the latter two being subdivided into AHCI and NVMe. AHCI is bootable on the cMP, NVMe is not. SATA SSD's regardless of form factor (m.2, 2.5 inch, whatever) require a SATA controller, you can't plug them direct into the PCI bus.
     
  4. barmann thread starter macrumors 6502a

    Joined:
    Oct 25, 2010
    Location:
    Germany
    #4
    Thanks guys, you explained it very well !
    I've rejoined the the upgrade game only recently, and missed all the discussions on current storage options, hence the basic questions ...

    I'm still running Mavericks for a number of reasons, so NVMe cards will not work I believe .

    Absolute disk speed is not a major issue for my applications - system and Adobe scratch drives are on 2.5" SATA SSDs already .
    I just thought I could get to SATA III speeds with little extra cost, which isn't the case appearently .

    I guess it's most economical for me to get a 2.5" 1TB SSD to replace the existing 'fast storage' I have now - 2x 320GB Velociraptors in Raid 0 .
    How's that for old school ? ;)
     
  5. kschendel macrumors 65816

    Joined:
    Dec 9, 2014
    #5
    I think you can still get the Kingston HyperX AHCI m.2 SSD's, but I have no idea about pricing. A 2.5 SATA drive is very likely your cheapest-per-Gb option.
     
  6. DPUser macrumors 6502a

    Joined:
    Jan 17, 2012

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