How to disable 2 of 3 GPU?

Hi, I have 3 GPUs in my PC but I want use only 1 to rendering with v-ray. I’m trying to disable 2 GPU in Extensions > v-ray > tools > GPU Device selection. I deselect 2 of 3 GPUs and save changes.
Even doing this seps V-ray is using all of my GPUs. Is the ofter way to disable them?

Could you please provide some additional info:
- Full progress log of a test GPU render.
- What does the CUDA device list display? (accessible through the Asset Editor > Settings > Renderer, it’s the button next to GPU)
- What is your GPUs utilization during a renderer? (see Task Manager > Performance)

Kind regards,
Peter