I have a 6900xt and no matter what tutorial I follow I am unable to make Vegas use my 6900xt. It always uses the CPU and not my GPU. This is frustrating because video play back is poor on my 5800x and it would be smoother on my 6900 xt. I cannot render videos using my GPU despite everything I have done. Is there anyone here who can help me?
How, I haven't heard of Sony Vegas for a while, I used to use that.
Back to topic. Let me see if I can help you out.
Video editors can be picky with the drivers, so I would advise you to use WHQL drivers, DaVinci won't work for me properly if I use a non-WHQL driver at all. It just won't see my GPU and thus not allowing OpenCL or GPU acceleration. It happened with my RX480 and RX6800.
Make sure you enable the GPU acceleration inside the application and you have version 15 or later.
If you can't see or select the card, then the driver advice is looking a go-to right now.
Also, Sony does not support Vegas anymore, they sold it to Magix, maybe have a look into their forum?