Should I use an NVME PCIe SSD or AHCI for 2009 Mac Pro?

Discussion in 'Mac Pro' started by PowerMac G4 MDD, Aug 4, 2016.

  1. PowerMac G4 MDD macrumors 68000

    PowerMac G4 MDD

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    #1
    Hi - So I was looking to buy a PCIe SSD and an adapter card for it, to run the thing in my 2009 Mac Pro. Upon looking around for SSDs, I noticed that there are several types of PCIe SSDs. I'm leaning towards the two I know best (and skipping NGFF ones): AHCI and NVME.

    From what I've read, NVME is newer... but is it more compatible/better to use? I'm running El Capitan in this 2009 Mac Pro. Found a Samsung SM951 chip (NVME) and an adapter card that supports such 2280 SSDs.


    Should I go ahead and buy the NVME 2280 PCIe SSD (Samsung SM951) + adapter card, or is it still a better bet using AHCI on this machine?

    -Thanks
     
  2. Fl0r!an macrumors 6502a

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    #2
    The cMP can't boot from NVMe and needs hacked or 3rd party drivers. Definitely AHCI!
     
  3. PowerMac G4 MDD thread starter macrumors 68000

    PowerMac G4 MDD

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    #3
    Thanks for the info. Almost bought a NVMe one! Now looking around for AHCI ones. Also noticed NGFF ones, but those are probably not the best ones to get, right?

    BTW, also looking for a compatible adapter card for an AHCI blade. Only thing is that these adapter cards I've been seeing have confusing descriptions of their slots. Cannot tell whether - for example - THIS one down here is meant for AHCI or for the NGFF ones that I don't want: https://www.amazon.com/SilverStone-...8&qid=1470383586&sr=1-4&keywords=PCIe+adapter

    Is it that the type of M.2 slot on the adapter doesn't matter, and that one's speeds just depend on which type of M.2 blade he uses? In other words, would this adapter take all types of M.2 interfaces, whether NVMe, NGFF, or AHCI?
     
  4. benjaprud, Aug 5, 2016
    Last edited: Aug 9, 2016

    benjaprud macrumors member

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    #4
    NVMe/AHCI relates to the way the SSD controller communicates over the interface (PCIe, SATA). The physical interface is the same for an NVMe or AHCI drive.

    It is however slightly different for a PCIe M.2 or a SATA M.2 drive. If you zoom closely on your link's picture, you can see the PCIe slot is labeled as "M-key" and has 4 pins on the right side while the SATA slot is labeled as "B-key" and has 5 pins on the left side.

    Most M.2 PCIe adapters are passive adapters (with no electronics on board) that route the M.2 connector pins to the right PCIe pins. The one you linked seems to route one M-key connector to the PCIe slot and another B-key slot to a SATA plug. The M-key connector should work fine with a PCIe drive. As long as it's a passive adapter, you don't have to worry about compatibility.

    If you're looking for a Samsung PCIe AHCI M.2 drive, there's the XP941 and the SM951. The latter exists in both AHCI and NVMe flavors so make sure to pick the right one.

    NGFF is just another name for M.2. Just make sure you don't buy a M.2 SATA drive or a mSATA (which uses another connector).
     
  5. isisism macrumors newbie

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    May 13, 2016
    #5
    I've just gone through looking for a PCIe SSD and I ended up going with the Kingston HyperX Predator that comes with the adapter. I've read that it's bootable and is OS independent. I'm getting it on Tuesday and can report back if you like, though I don't know what day I'll be able to get it popped in and tested. (early 2008 MP)
    https://www.amazon.com/gp/product/B00V01C4RK/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

    It comes with Acronis if that makes any difference to you.

    If you buy a different drive, here's the adapter I was looking at that will work:
    https://www.amazon.com/Lycom-DT-120...8&qid=1470528191&sr=8-1&keywords=lycom+dt-120

    I was originally looking to get a Samsung XP941 which is ACHI, but could only find a 512gb and didn't want to spend that much. Did find the 256gb at an Australian store but didn't know if I would have to pay any import fees shipping to US so decided against that.
     
  6. benjaprud macrumors member

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    #6
    Several users reported trouble trying to run BootCamp with the HyperX Predator. If you intend to do so, you'd better stick to the Samsung drives.
     
  7. PowerMac G4 MDD, Aug 8, 2016
    Last edited: Aug 8, 2016

    PowerMac G4 MDD thread starter macrumors 68000

    PowerMac G4 MDD

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    #7

    Good job clearing that up for me - well explained! Curious, though, why I have seen NGFF drives for cheaper prices. Seems like ones sold as "AHCI" drives cost much more. If I can truly get the same speeds from an "NGFF" one as I would from an "AHCI" one, I'd just get the NGFF one. Unless, of course, you were saying that any PCIe SSD can be referred to as "NGFF," regardless of whether it's AHCI or NVME. I guess some say both and some show only one or the other.
    --- Post Merged, Aug 8, 2016 ---

    Thanks for that information and help! Another user here has reported that people have had Bootcamp issues with this card, though. The adapter looks right, but I think I'll go with Samsung for the card. Bootcamp is one of the reasons I'm looking to ditch my sketchy SATA SSD RAID set-up.
    --- Post Merged, Aug 8, 2016 ---
    Okay, I found one that is reasonably-priced and seems to be AHCI. However, the benchmark shown in one of the images seems rather lacking. I'm hoping to achieve the max of 1500MB/s that my 2009 Mac Pro can get with such a drive. Is there a chance that this was simply a lame-duck test? 700MB/s is only a couple hundred over the speeds I get with my two SATA SSDs in RAID. The read is nearly 1000, which is good, but I am still hoping for a little bit more. I'd like both to be over 1000, if I'm going to pay this money.

    http://www.ebay.com/itm/Samsung-XP9...072550?hash=item3d2152b166:g:WXcAAOSwRoxXm2zA
     
  8. benjaprud, Aug 9, 2016
    Last edited: Aug 9, 2016

    benjaprud macrumors member

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    #8
    Anandtech tested the 512 GB model of this drive at about 1137/982 MB/s read/write on a Mac Pro (their review is great if you want to read it). The 256 GB model has a slightly lower write throughput though (a bit lower than 900MB/s). Different methods of testing or benchmark softwares can show different numbers. Review benchmarks are usually done on empty drives, which will show better numbers than on a full drive. Windows 7 has apparently no TRIM support for this drive (at least at the time Anandtech wrote their review).

    If that's not enough you should aim for the SM951 AHCI (review on Anandtech) which is faster and the fastest bootable SSD you can put in a Mac Pro (or an Apple SSD but these are harder to find and more expensive). You shouldn't notice much of a difference in a daily usage between the two.
     
  9. flowrider macrumors 601

    flowrider

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    Nov 23, 2012
    #9
    What's that? Do you mean SM951 to XP941?

    Lou
     
  10. benjaprud macrumors member

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    Apr 9, 2015
    #10
    Oh yeah sorry, That's the SM951 AHCI. Corrected in previous posts, thanks.
     
  11. xnathanh macrumors newbie

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    Mar 11, 2016
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    irvine
    #11
    anyone know where to buy sm951 MZHPV512HDGL-00000 achi?? i am in us thanks!!!
     

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