That’s what the GPU is used for; when you put it to work, the normal operations it does don’t work as well. You’ll find the same will happen with most other GPU renderers.
Only three real options: either use the CPU, buy a cheap second GPU for general computer graphics while your other is used for rendering or render when you aren’t using the computer.
There might be a efficiency increase in the future, I don’t know.
Possibly there might be another solution, I don’t know about that either.
Hope that helps in one way or another,