Slot organisation...

Discussion in 'Mac Pro' started by Killerbob, Feb 4, 2013.

  1. macrumors 6502a

    Jan 25, 2008

    I have the MacPro3,1, and I have decided to do all the upgrades I possibly can, whilst not holding my breath for the 2013-Mac Pro...

    So, a new GTX680 graphics card, and an Accelsior 960GB SSD card are on their way to me as I write this.

    Preparing for the installation I have a question:

    Does it matter how I install these two cards in the MP? I.e. any particular reason why I would put the Accelsior card in Slot1 and the GTX680 in Slot2, or vice versa? They both require PCIe 2.0, and hence I can't use Slots 3 and 4.

    My logic in putting the Accelsior in Slot1 is that this gives some space between the two cards.
  2. macrumors 6502a

    Dec 20, 2010
    Generally speaking, I believe the video card is supposed to go in slot 1, however I think some people have had varying results in slots 1 or 2, depending on the card. I know when I installed my 670, I put it in slot 1 where my 5770 had been and I had no issues. Not sure if there would be any downside to putting the video card in slot 2 though.
  3. macrumors 6502a


    Dec 14, 2009
    Helsinki, Finland
    I won't contradict this information, as I really do not know, but on another level the card producing more heat should always have as much air around it.

  4. thread starter macrumors 6502a

    Jan 25, 2008
    That was my logic as well. If I put the graphics card in Slot1, and the Accelsior card in Slot2, there will be very little space between the two cards. However, if I switch the two cards, the Accelsior card will be in Slot1, which is a dbl. space slot, and hence have 1 slot height up to Slot2 with the graphics card.
  5. macrumors 65816


    Nov 15, 2010
    Edinburgh, UK
    The 6XX cards produce less heat than you may be used to with, say the 5870. Most of it will be generated on the top surface where the card cooler is doing its work. I wouldn't worry which slot it went into.
  6. macrumors Core


    Feb 9, 2008
    San Jose (CA)
    Even though slot 3 and 4 only run in x4 mode, they have more than enough bandwidth for the OWC Accelsior card.
  7. thread starter macrumors 6502a

    Jan 25, 2008
    Correct, but the MacPro3,1 only has PCIe2.0 in slots 1 and 2. Putting any card, graphics, Raid, or SSD card, in slots 3 and 4 equals half transfer rates, at least if the card is intended for version 2.0 or 3.0...
  8. macrumors 65816

    Jan 1, 2007
    San Francisco
    I remember when I had my 5770 in slot 2, the expansion slot fan would spin up quite a bit. When I put it back in slot 1 it went back to normal. Now I have a 670 in slot one and the only time the expansion slot fan spins up is on a fresh boot. I I have to stress the video card for the fans to slow down. I wonder if slot 2 would be the same results with my 670?
  9. macrumors 68040


    PCIe 1.0 x4 has a bandwidth of 1000MB/s. As far as I can see, your SSD card tops out at 800MB/s. Should work just fine.
  10. hfg
    macrumors 68030


    Dec 1, 2006
    Cedar Rapids, IA. USA
    The lower 2 slots appear to be the same spec, just have double spacing for the video card. You should be able to install either card in either slot, although if you have a double-wide video card in slot-2 it will prevent use of slot-3.

    Mac Pro Developer Note
    PCI Express Architecture

    The Mac Pro has four internal PCI Express (PCIe) links connected to the North Bridge IC and South Bridge
    IC. Two of the links provide 4-lane expansion slots supporting the PCIe 1.0a standard at 2.5 GHz. The
    other two links provide 16-lane 5.0 GHz PCIe 2.0 interfaces: one double-wide graphics slot and one
    expansion slot.
  11. thread starter macrumors 6502a

    Jan 25, 2008
    According to the Accelsior details inserting the card in a PCIe ver. 1.0 equals lower transfer rates... "PCIe 2.0 x4 slot or better is required. Use of a PCIe 1.0 x4 slot will reduce performance."
  12. macrumors 68040


    Judging by the appearance of the card, it's actually PCIe x2 and not x4, which means it would be limited to 2x250MB/s on PCIe 1.0, but runs on 2x500MB/s on PCIe 2.0.
  13. thread starter macrumors 6502a

    Jan 25, 2008
    You are probably right. On OWCs web-page it says "Interface - PCIe 2.0 x2".

    Seeing as the max. transfer rate from the card is approximately 800MB/s, that's why it needs ver. 2.0.

    Anyways, I think I'll go with the Accelsior card in Slot 1, and the GTX680 card in Slot2.
  14. macrumors 68030


    Feb 4, 2010
    For what it's worth, I have a 5870 in slot 1, and a full-size Areca 1880ix-12 RAID card in slot 2, just a few millimeters above the GPU, and the temps have been fine for over a year of heavy video editing use every day.

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