Problems with external graphic card on MacBook Pro 16

Hello,

Since upgrading from version 16 to 17 of DVR, there are huge hardware compatibility problems with my AMD WX9700 external graphics card. I had no problems with version 16.
The problems are the slowness of the DaVinci Resolve software. Can't play smooth video. The interface is very slow, manipulations are impossible.
After various searches, I can't find any information. I finally unplugged the external card, and against all odds, it works perfectly on the MacBook Pro. I assume that this is a defect in DaVinci's support of the card because all the other software works correctly with the external card (Adobe Photoshop, Premiere Pro, After Effect, etc.).
Does anyone here have any information on the support of external Gpu's by version 17? Or are any of you working on Mac systems experiencing the same problem?
I'm sorry, I just bought the studio licence to be able to use both graphics cards simultaneously, which is not possible with the free version.

Thank you very much for your help,

PS: I am French so I am using a translation software to write this message.
PS 2 : i use Mac OS 10.15 Catalina

It works fine for me, but I'm under the impression that Resolve works best if the two cards (internal and external) are the same. I know, that doesn't help you much now that you already bought it.
And then, the eGPU doesn't do much for editing, since its connection is slower than the internal one. It will rather cut down on rendering times of demanding filters, like NR or optical flow.
One thing to try, though: are your cards set to Metal or running on Auto?

Thank you for your reply.

When I first started DaVinci Resolve, I noticed the problem of the software being slow. I went into the preferences to see how the GPU settings were set. Indeed, everything was in auto.
I changed the settings to Metal, then to OpenCL. In both cases, the problem was the same.

What I notice is that the hardware configuration between version 16 and 17 has not changed at all. So for me it's another problem. I will continue the various tests and I will come to update the topic.

Hello,

For those following this thread, here is the (very simple) reason that solved my problem.

On Mac systems (OS Catalina), when you right click on the icon of an application, for example DaVinci Resolve 17, you can display the information related to the application. In this menu, there is a checkbox that allows you to say that when this application starts, it uses the external graphics card (eGPU) first. But I went by chance to uncheck this famous box. Since then, when I run DaVinci Resolve, everything works fine, and everything is smooth again.

It's weird, but that's how it is.

Interesting. I never checked that box in the first place.

Confirming that this is the solution! Thank you! Unchecking the box fixes the problem. I'm running OSX 10.15.7 with resolve 17.2.2. Back to work!