How to restrict to cycles use only 90% of gpu? For example redshift use always between 80-90% and because of that i can work with something else when render on video card. But when i put render on cycles i can forgot about using PC while rendering.
From the Blende manual on GPU Rendering
Why is Blender unresponsive during rendering?
While a graphics card is rendering, it can not redraw the user interface, which makes Blender unresponsive. We attempt to avoid this problem by giving back control over the GPU as often as possible, but a completely smooth interaction can’t be guaranteed, especially on heavy scenes. This is a limitation of graphics cards for which no true solution exists, though we might be able to improve this somewhat in the future.
If possible, it is best to install more than one GPU, using one for display and the other(s) for rendering.