iMac Pro eGPU Options + Benchmarks

Discussion in 'iMac' started by blackwoodfx, Nov 1, 2018.

  1. blackwoodfx macrumors member

    blackwoodfx

    Joined:
    Nov 15, 2010
    Location:
    Las Vegas, NV
    #1
    We have fully loaded iMac Pros (18-core, 128GB RAM, 4TB SSD, VEGA 64 16GB GPU). But we are still choking on large VR footage and RED 8K footage (to use two examples). We are exploring adding external GPUs to help with this but we are having trouble finding concrete information about (1) which GPUs we should be looking at and (2) exactly what kind of performance benefits we could expect.

    Does anyone here have any solid leads on how we can further improve on the loaded iMac Pros we are already running? Many thanks in advance.
     
  2. wardie macrumors regular

    Joined:
    Aug 18, 2008
    #2
  3. jjjoseph macrumors 6502

    Joined:
    Sep 16, 2013
    #3
    I hate to suggest it but your pushing into PC hardware realm. What programs are you using? eGPUs are great but have major bandwidth bottlenecks.

    Recine-x uses a lot of CPU or Redrocket, Resolve lots of GPU but decodes certain files on cpu, but if you add eGPU your bottlnecked by the thunderbolt3, and Adobe CC uses both CPU and GPU but your way better off with the PC Nvidia version to get full GPU usage.

    Your setup is awesome but your pushing the upper limits of what it can do. Also if you bought a .R3D debayer card like a red rocket, you would have to build en external PCI bridge. Again all cumbersome and bottlnecked.

    I use macOS everyday but sounds like you need a windows machine. Dual Xeon with 2x2080ti sounds about right. Oh and put in a Redrocket as well.
     
  4. joema2 macrumors 68000

    joema2

    Joined:
    Sep 3, 2013
    #4
    You should probably talk to a consultant experienced in that area. Whether iMac Pro with eGPU or PC, it's a lot more complicated than just throwing hardware at the problem. There are many "blind alleys" due to the software not fully leveraging the hardware. It's easy to spend lots of money on hardware without major benefit. Max Yuryev has done a lot of eGPU testing, including some RED 8k material. You could contact him; if unable he could possibly direct you to somebody else. See his web page.
     
  5. jjjoseph macrumors 6502

    Joined:
    Sep 16, 2013
    #5
    I work in film and TV and Puget Sound is one of the best resources.

    Search through their website.

    https://www.pugetsystems.com/
     
  6. joema2 macrumors 68000

    joema2

    Joined:
    Sep 3, 2013
    #6
    Puget has a good reputation but I'm not sure the OP is looking to throw away his entire fleet of iMac Pros and switch to Windows. If he was why even post on a Mac forum.

    He didn't state what editing software he's using but if it's FCPX the only option would be (a) switching to another NLE or (b) build a *very* high-end Hackintosh. Neither one of those is easy if his organization is already deeply invested.

    If all his software is cross-platform (Premiere, Avid, Resolve, After Effects, etc) then switching to Windows is more straightforward.

    The problem with adding an eGPU to an 18-core iMac Pro, is it's already fast on the CPU side, and the Vega64 GPU isn't slow. Yes there are faster ones, but are they faster with his exact software and workflow? He doesn't even know for certain if the current problem is due to a GPU limit. The solution might be as easy as using proxies.

    If it's a typical post production pipeline, the finishing stage is often done by dedicated machines and software. In that case the solution might be keep the iMac Pros but add dedicated (maybe Windows) machines for finishing.
     
  7. BigBoy2018 macrumors 6502a

    BigBoy2018

    Joined:
    Oct 23, 2018
    #7
    Not helpful for the OP, but my only comment is, why even bother with 8K? Hollywood movies you watch on a 70 foot wide screen are 'only' in 4k and they look great, so just curious what your use case is for 8k.

    The VR stuff I get, just was wondering about the other. :)
     
  8. joema2 macrumors 68000

    joema2

    Joined:
    Sep 3, 2013
    #8
    Many Hollywood movies are shot in less than 4k, and many theaters have yet to upgrade beyond 1080p (technically DCI 2k).

    Of the nine 2018 Hollywood films nominated for a best picture or best editing Oscar, none were filmed in 4k. Five were shot on film, five were shot digitally, one used film and digital acquisition. The film productions were scanned and digitally edited.

    The digital productions were all filmed in 2k up to about 3.7K, and all used either the ProRes or ARRIRAW codec. The single exception was I, Tonya which had limited sequences shot in 6.5K. None were shot with RED cameras. None were edited at original capture resolution -- all were edited using essentially off-line proxies at 1080p.

    https://blog.frame.io/2018/03/05/oscar-2018-workflows/

    Re why shoot at 8k, there are valid reasons. See below description starting at 2:35. It's not about delivery resolution, rather post production flexibility and product shelf life. One analogy is why in 1965 did NBC shoot almost all prime-time shows using expensive color film, when only a tiny % of households had color TVs? Because they knew the viewing technology would improve and shooting in color was an investment in that future.



    That said, the decision to shoot in 8k should be well-researched with lots of testing to validate the planned post production workflow -- before cameras are purchased and before production footage is shot.
     
  9. blackwoodfx thread starter macrumors member

    blackwoodfx

    Joined:
    Nov 15, 2010
    Location:
    Las Vegas, NV
    #9
    Thanks for the reply and sharing the link. Good data in there. The issue with Nvidia is Mac OS compatibility is non-existent, so to run an iMac Pro with Nvidia cards means booting into Windows environment and, at that point, we'd be better off running a PC. We're trying to stay within Mac OS which unfortunately means we're stuck using AMD.
    --- Post Merged, Nov 5, 2018 ---
    We had multiple RED Rocket-X cards but dumped them once the returns were diminished. They do nothing to support 8K RED RAW with an iMac Pro now, unfortunately. I think you're right about the rest... Truly hate to abandon Mac OS and enjoy the comfortable workspace offered by Final Cut Pro X, ProRes, etc.
    --- Post Merged, Nov 5, 2018 ---
    We use 8K for about 90% of the work we do. Primarily, VFX plates, ripping still frames from motion video, VFX roto/stabilization work, etc. Higher-resolution (along with frames and DR) are part of our main workflow.
    --- Post Merged, Nov 5, 2018 ---
    Thank you. We'll have a look today.
    --- Post Merged, Nov 5, 2018 ---
    Good general answers here for anyone else looking at the same problems. Thanks for the post. With the iMac Pros, our needs are primarily handling 8K RED RAW footage for VFX purposes, and delivering fast editorials with FCPX. We also use DaVinci for multi-light grades and we have a dailies routine that rips stills from 8K footage for fast-turnarounds/looks, etc. While much of that work could be done within a PC platform, the problem is cost of retraining and equipment replacement.

    The iMac Pros give us almost everything we need. Another 20% performance gain and we'd be right on our sweet spot for deliveries. That's where we hope eGPU could provide a solution.
     
  10. ticotoo macrumors member

    Joined:
    Jul 8, 2010
    #10
    First decision point is if you need CUDA. I have a gtx1080 & Titian V in sonnet breakaway 650’s running together on my iMac pro in high Sierra (also on 2018 map). The problem in using Nvidia cards is that apple doesn’t provide drivers & you have to rely on Nvidia web drivers which are specific to the version of macOS (including security updates). Of course the titanV is extremely fast in OpenGL. Search for my greekbench scores on the GeekBench webpage.

    Nvidia have not released drivers for Mojave yet. The gtx is faster than my vega64.
    The titanV (Volta) drivers were in the xx.108 version released back in sept. However Nvidia pulled those & the lastest xx.40.108 don’t appear to have the Volta kext.

    If you do not need CUDA, then get vega64’s in a eGPU. My BruceX times when from around 90-130 seconds using various older macs (mp2010, MBP;2012,2014) to around 19 sec when using a vega64. However, fcp would not use the eGPU until Mojave’s without patching HS (see eGPU.io webpage). The advantage of using AMD is that it’s plug & play. The other problem with the gtx1080 is Nvidia needs various scripts to get it to run. The eGPU.io webpage has those scripts & information needed. Also Nvidia has not released Mojave drivers for any of the pascal, tensor, carde. Ie 1080x 2080ti.
     
  11. joema2 macrumors 68000

    joema2

    Joined:
    Sep 3, 2013
    #11
    He already has a Vega64 in his 18-core iMac Pros. I just ran the BruceX benchmark on my 10-core Vega64 iMac Pro, and it did 13.5 seconds. I don't see how adding an eGPU with essentially the same GPU he already has would give the OP the major improvement he needs. He doesn't need just a little bump but a big improvement.

    However it's theoretically possible to use a faster Vega eGPU or multiple faster eGPUs, as done in this Bearfeats.com test. Two eGPUs with Vega Frontier cards were faster than then internal Vega 64 GPU, at least for some software: http://barefeats.com/imacpro_vs_pt6.html

    For a real-world production situation this would have to be rock-solid reliable, not some flaky thing as might be done for an overclocking test.

    Re CUDA, he's editing in FCPX -- that doesn't use CUDA so it doesn't seem useful for that aspect. He also uses DaVinci for color and other software for VFX, so maybe that phase could be offloaded to a high-end Windows workstation.

    Bearfeats.com tested three Vega cards in a 2010 Mac Pro using OpenCL and it was faster. In their test of a Titan XP, CUDA was only modestly faster than OpenCL: https://barefeats.com/opencl_v_metal_resolve.html On the DaVinci Resolve forums they report varying results -- CUDA is not always faster.
     
  12. ticotoo macrumors member

    Joined:
    Jul 8, 2010
    #12
    https://browser.geekbench.com/v4/compute/3087655
     

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11 November 1, 2018