Arriraw Transcodes in Resolve

Rick Dawson Sep 24, 2015

  1. Hi all.... I have a new Mac Pro 12 core Dual 700 GPU's. I'm trying to get faster transcode speeds then 50 FPS, here's what else is going on:

    Read: Thunderbay 4 Raid 0
    Write: Glyph Studio Raids Raid 0 and have tried internal SSD

    Debayer settings in resolve 1/2, 1/4

    transcode codecs Pro Res 4444, Pro Res 422 LT, DNX 36,

    Is anyone running external GPU's for increased speeds?
  2. I am pretty sure you can't run an external GPU you are stuck with the trash in the trashcan...;-)
  3. If you're talking about Arriraw Open Gate, the data rate for that format is close to 300MB per second. So at 50fps, you're reading at almost 600MB per second, which is probably near the limit of what a 4 drive Thunderbolt array can provide. Even with "standard" Arriraw 2880x1620, you're talking over 200MB per second. So your drive throughput is probably pretty significant here.

    The Mac Pros have numerous issues, but the speed of the GPU's on most current formats that aren't Red is not really one of them. And while they are not as fast as the most recent Nvidia cards in a fast PC, they are not slow. Of course, you are dealing with software based Open CL, not hardware accelerated Cuda, so there's that.....
    Jason Myres likes this.

  4. Thanks Michael... I've tested Open Gate and Raw, same results. Have you heard of anyone running Cuda cards via expansion chassis?

  5. It is not permitted in OS X. Not to mention that Thunderbolt 2 is still lane limited (4 lanes) which is not really enough to allow full speed data transfer between the card and the system, particularly when the card is a 16 lane card (as most GPUs are). If you must stick with the Thunderbolt chassis, you might try to wring every last bit of speed out of it by replacing the spinning drives with SSD's. Other than that, I don't really have any other suggestions.

    BTW, the biggest problem with the Mac Pro cylinders and their GPUs is that far too many of them are prone to putting horizontal "hits" in images, particularly when running Resolve. This is a known issue and there is no current solution other than returning the Mac and getting a replacement. Some have this problem, some don't.
  6. On my machine with two 1400Mb/s + disk arrays and a single GTX Titan GPU running OSX 10.8.5 I typically get 70-78fps arriraw renders to ProRes444
  7. No external GPU support over thunderbolt 1 or 2. Red rocket is the exception!
    Thunderbolt 3 will solve this exact issue and open up a whole new world of GPU render farms and computer possibilities.

    I only get 35 fps with arri raw with cMP 12 core and Cubix, so at 50 you're looking pretty good ;)
  8. Yep Michael,

    I had to get mine replaced! Took a week to get them D700 in stock... So far so good, fingers crossed.
  9. We have a number of these machines (about 15 of them, I believe) and the GPUs have been replaced on all but 2 of them. Some have been replaced more than once. I no longer recommend them (haven't for a while), especially for use with Resolve, and quite frankly wish Apple would either "officially" discontinue them, or allow another manufacturer - HP, for instance - to build a "Z840 Mac Edition" and let us get on with our lives.
    Erik Wittbusch likes this.

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