External PCIe chassis for GPU rendering with MacPro 5,1

Discussion in 'Mac Pro' started by balt, May 2, 2015.

  1. balt macrumors newbie

    Mar 5, 2009
    Hi all,

    I'm still working happily with an over the years upgraded mid 2010 MacPro 5,1. It's got SSDs now, a GTX680 graphics card, and much external storage. On the CPU side, the relatively minor speed improvements over this dual hexacore machine don't really warrant upgrading, in particular now that most of my 3D render engines I use are CUDA based. I've so far always built PCs that are just used as render stations, but I'm really sick of getting slow render performance for previews out of my mac. So I've decided to upgrade now that the GTX Titan X has been released (or is just about to).

    What I'd like to do is buy an external PCIe chassis and stick 4 Titan X's in there, so it'll need to be a full size tower with a 1200W or so PS.

    Has anyone done this or something similar before? If so, what brand chassis have you had success with?


    - Balt
  2. Synchro3, May 2, 2015
    Last edited: May 2, 2015

    Synchro3 macrumors 68000


    Jan 12, 2014
  3. mattspace macrumors 6502a


    Jun 5, 2013
    Never had call to use them, but these guys have been around doing this stuff for almost 30 years, and probably have a solution.

  4. balt thread starter macrumors newbie

    Mar 5, 2009
    Thanks guys, looks like you've found the same devices I've found... I just haven't seen anyone use these successfully for GPU rendering. I was hoping someone else did that with a MP 5,1 before I spend substantial funds flying blind...


    - Balt
  5. EHuntington macrumors newbie

    Dec 23, 2013
    At work we have a Magma PCIe expansion box that we originally used for a networked RAID storage server, but has since turned into a general use server. We have two Quadro 4000 Mac edition cards in there now and a few network and esata cards. Ours is attached through a 2009 Xserve, but I assume the Mac Pro would work similarly. I think in general it would work, but if you used a Magma box I think you'd run into power issues. The Quadro 4000's we have in ours are attached through molex to pcie power adapters. The power supply doesn't have the cabling for any pcie power. This box is an older model, so maybe the new ones are different?
  6. thornslack macrumors 6502

    Nov 16, 2013
    I don't think I saw it mentioned yet, but there's also the cubix expander. I think barefeats has some benchmarks using it.
  7. balt, May 3, 2015
    Last edited: May 3, 2015

    balt thread starter macrumors newbie

    Mar 5, 2009
    Interesting, thanks for pointing this out...

    Found their site here: http://barefeats.com/gpu680v7.html


    - Balt
  8. MacVidCards Suspended

    Nov 17, 2008
    Hollywood, CA
    YMMV in later OS's.

    Best to read up at Pro sites like lift gamma gain and Creative Cow.

    Apple really didn't like having nMP made to look so foolish so I think 10.9 brought some pain to expansion chassis that hasn't been fixed yet.

    But as I said, best to read up from Pros or ask the Cubix folks themselves.
  9. Sedor macrumors member


    Dec 28, 2013
    I have a Amfeltec GPU Cluster with three video cards in it running.
  10. Tutor, May 4, 2015
    Last edited: May 4, 2015

    Tutor macrumors 65816


    Jun 25, 2009
    Home of the Birmingham Civil Rights Institute
    I have tested a $200 (USD) Amfeltec Splitter (Supports up to 4 GPUs per splitter card - http://amfeltec.com/products/flexible-x4-pci-express-4-way-splitter-gpu-oriented/ ) on a MacPro2,1 (2007) with four GTX780 6G video cards (2 in MP and 2 externally connected by splitter - see 1st pic, below). The MacPro 2007 will support only 4 GPUs stably, even if externally connected (i.e., it makes no difference which external chassis you use and it makes no difference how you allocate the GPUs internally or externally at least with OS 10.9.2). That's because of the IO space limits of the 2007 MP. I'm not sure whether that limit applies to the 2009 and later MPs. You can put up to three double wide GPUs internally in a MP 2007 to MP 2012: See http://forums.macrumors.com/showthr...ld+mac+pros+can+make+respectable#post18872245 and http://forums.macrumors.com/showthr...ld+mac+pros+can+make+respectable#post18887464 . Extra PSU is required in all cases for three or more recent GTX GPUs with significant rendering ability. Second pic, below, shows rack module of 8X GTX 780 6G GPUs from which I ran test using 2 of them. The rack of 8x GTX 780 6G GPUs is for my Supermicro server.

    Attached Files:

  11. balt thread starter macrumors newbie

    Mar 5, 2009
    Thanks for all the links Tutor. This is just to confirm I've been following up with all of those and some other bits I found, and it clearly comes down to the amfeltec product being by far the least expensive and flexible option:


    Those go for about $500 plus shipping. A long shot from the $3500 and more for the enclosed chassis by cubix.


    - Balt
  12. Flint Ironstag macrumors 6502a

    Flint Ironstag

    Dec 1, 2013
    Houston, TX USA

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