Resolved Velocity Duo X2 Card (Very slow performance)

Discussion in 'Mac Pro' started by Ursadorable, Jan 15, 2016.

  1. Ursadorable macrumors 6502

    Ursadorable

    Joined:
    Jul 9, 2013
    Location:
    The Frozen North
    #1
    So I upgraded my cMP 3,1 with a Velocity Duo x2 card with two Samsung 840 Pro 256GB drives.

    I pulled these drives from my Windows PC, and I know they work fine.

    The Duo is plugged into the top PCI Slot (marked x4). It's getting a R/W speed of 190MB/sec with Disk Speed Test which is horrible performance from a SSD. Infact, I did the same speed test on my AppleRAID mirrored 4TB drives and got about the same speed.

    I also tried in the 3rd slot (x16) above the video card, and the cMP wouldn't even see the card.

    I'm at a total loss here..

    At first I tried it as a soft AppleRAID (stripped), same speed.. then I tried using it's on-board Marvel BIOS making a hardware stripped RAID. Again, same speed.

    Any suggestions?
     
  2. hfg macrumors 68040

    hfg

    Joined:
    Dec 1, 2006
    Location:
    Cedar Rapids, IA. USA
    #2
    Try PCIe slot #2 nearest the video card. Slots 1 & 2 are PCIe 2.0 x16 whereas slots 3 & 4 are only PCIe 1.0 x4. As a test you could also swap the video card and the DUO card into slot 1.

    How did you enable hardware RAID on the DUO? Last I heard it had to be configured on a BIOS PC.

    MacPro 3.1 technical specs:

    This model has two PCIe x4 expansion slots and two PCIe 2.0 x16 expansion slots (in the default confugration one PCIe 2.0 x16 slot is occupied by the graphics card). Apple also reports that "all slots provide mechanical support for 16-lane cards [and supports] 300W combined maximum for all PCI Express slots."
     
  3. Ursadorable thread starter macrumors 6502

    Ursadorable

    Joined:
    Jul 9, 2013
    Location:
    The Frozen North
    #3
    I tried that one, the card wasn't recognized in it. :(
     
  4. hfg macrumors 68040

    hfg

    Joined:
    Dec 1, 2006
    Location:
    Cedar Rapids, IA. USA
    #4
    Did you try re-seating the card in the slot a few times? How about putting your video card in slot 2 and put the DUO card in slot 1?
     
  5. Ursadorable thread starter macrumors 6502

    Ursadorable

    Joined:
    Jul 9, 2013
    Location:
    The Frozen North
    #5
    I think I found the issue.

    It seems that when the drive is formatted on the card in the top two slots, it's not recognized in the bottom two slots. Which is very odd..

    However, I booted off a thumbdrive and it showed the drive when in the x16 slot, so I went ahead and reformatted it and installed off a time machine backup, and now it works.

    Still not sure why I had to reformat the drive because I moved the card to a different slot.
     

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