Choppy playback and no render benefits when using GPU Acceleration on Mac Pro 2013

[Andrew Kimery]

[Morten Hilmer] “When I disable the GPU and use the Software Only, everything play back very fine. “

Starting with later builds of Mavericks (and continuing into Yosemite) some owners of the new Mac Pro have reported problems when running Resolve and/or Premiere Pro (two GPU-centric apps). Turning off GPU acceleration or booting the machine into Windows are two workarounds so the would seem to be with Apple’s drivers for the twin GPUs in the new Mac Pro.

[Morten Hilmer]

Thanks a lot for your answer. That means it is an Apple software / driver issue and not a problem with my Fire Pro D500 graphic card itself or the Premiere Pro?

[Dennis Radeke]

Do you have the source and program monitors set to ‘full’ on the bottom of each panel/window? If so, I would pull them back to 1/2 or 1/4. Likely your monitor isn’t a 4k display, so turning that down to 1/4 is the most logical answer.

Also note, that 4k H.264 is quite difficult to playback even on current machines.

HTH
Dennis – Adobe guy

[Morten Hilmer]

Hi Dennis and thanks a lot for your explanation and advice. The “dropping frames” is the same no matter if I choose 1/1 – 1/2 – or 1/4. That is the weird part I think. The second strange thing – and the one thing that really make me curious is that the “software only” plays the 4K footage without dropping frames.

It is the same behaviour when I look the media files in the media browser as in the timeline.

The only reason why I use the GPU mode is that the render time for the timeline is much shorter.
Though the time for exporting this 2 minutes and 39 seconds video with only one video track and one audio track into a 4k mp4 takes 15 minutes and 31 seconds no matter if I use GPU or Software in the media encoder.

Shouldn’t it be faster when enabling the GPU?

I really appreciate that you guys are taking your time to help me.

[Dennis Radeke]

[Morten Hilmer] ”
The only reason why I use the GPU mode is that the render time for the timeline is much shorter.
Though the time for exporting this 2 minutes and 39 seconds video with only one video track and one audio track into a 4k mp4 takes 15 minutes and 31 seconds no matter if I use GPU or Software in the media encoder.

Shouldn’t it be faster when enabling the GPU?”

Not necessarily. As you will hear me say, it is all about balance. If we put a full load on the GPU, and not on the CPU, we’re just moving the problem. Ideally, we are trying to balance and get full use out of both CPU and GPU wherever possible.

Rendering or creating output is more the purview of the CPU. The GPU is used in part but really the bulk of AME usage is going to be the CPU.

How is the GPU used then? If there are GPU accelerated effects in the timeline before you render, the GPU can be used to accelerate aspects of that process.

More recently, we have added the feature of allowing the GPU to assist in the decode of the video for large frame camera formats like RED, ARRI & C-DNG.

HTH,
Dennis