DaVinci Resolve + Radeon VII Functionality

Hi all,

Looking for some help - am running a 2019 MacBook Pro with a Radeon VII externally via a Razor Chroma eGPU box. Feel like it's not running as usual - here's a screen grab during a render showing the internal MacBook GPU maxed out but the Radeon VII barely doing anything. Currently it's set as the Main Display GPU but I can't figure out how to get it to do the heavy lifting. Ideas?

Screen Shot 2021-08-05 at 2.50.16 PM.png (610.36 KiB) Viewed 884 times

Presuming that you've got Resolve set up to use both the internal radeon pro and the external radeon VII, what's likely happening is that the slower internal card is effectively throttling the faster external card. In my experience, Resolve doesn't know how to load balance optimally with multiple GPUs, it just splits the workload up equally among all GPUs even if one is a lot more powerful than the other.

Try forcing Resolve to only use the Radeon VII by un-checking 'use display gpu for compute' and manually selecting only the Radeon VII in preferences.

You might also be bottlenecked somewhat by the Thunderbolt interface, but that's just life with an eGPU.

Thanks for the response - I feel like the check box for 'use display gpu for compute' has gone wandering in recent versions - I'm running 17.2.2 Studio version and here's what I can see under the GPU section in settings:

Screen Shot 2021-08-10 at 3.14.04 PM.png (479.85 KiB) Viewed 512 times

So it has; that option may not even exist anymore.

Uncheck 'Auto' for GPU selection and then uncheck everything except the Radeon VII in the list of GPUs. With this setup Activity Monitor should show the Radeon VII loaded and the 560X idle, which should be faster than using both GPUs.

Just another data point, I found similarly.

6800XT + WX9100 + Vega 64 with GPU selection set to "Auto" was substantially slower than just selecting the 6800XT.