I am noticing that when I am rendering with Cycles using GPU on my Windows 10, the Windows gets a little bit slower but still usable. Often times, when GPU is fully utilized, entire windows becomes super choppy, but with Cycles, it just gets a bit slower, but not completely choppy.
I know there is a concept of GPU thread priority in Windows, which can be set: https://docs.microsoft.com/en-us/windows/desktop/api/dxgi/nf-dxgi-idxgidevice-setgputhreadpriority
It feels like Blender is already using it (?) but at the same time, it does not seem to be as effective as V-Ray GPU low GPU thread priority toggle, which sets GPU to the lowest priority and allows me to work and use other software while GPU is rendering. So it’s this weird state, where Cycles GPU priority is low enough to not make Windows grind to a halt, but not low enough to allow user to do something else alongside GPU rendering, such as watching video.
Is this correct? And is there perhaps some way to change the GPU thread priority in Cycles to the lowest one possible?
EDIT: Furthermore, it appears that Cycles GPU rendering has different priority when running as a viewport renderer VS when running as a final render. The priority of viewport renderer mode actually seems to be higher, making entire UI very sluggish when viewport render is updating. This doesn’t make much sense… Shouldn’t it be the other way around, if anything? Here’s a video showcasing the issue:
While update of viewport renderer makes the entire UI super choppy, final rendering slows down the UI a bit but still keeps it relatively fluid.
The ideal case scenario would be to have option to have very Low GPU thread priority for both viewport renderer and final renderer, so that when rendering in viewport, update doesn’t kill interactivity, and when rendering final, user can switch to other software instead of having the computer completely unusable.
I hope this can be fixed. Thanks.
EDIT2: Here’s a proof that it’s possible: