You can adjust the RT settings (bundle size/rays per pixel) to control the interactivity. F.e. reducing the # of rays per pixel will make the system more responsive. Another solution is to get a second GPU for rendering. F.e. my laptop has an Intel card which is used for the viewports and the Windows UI, and an nVidia GPU which I can use for rendering. There is also the CPU version of the RT.
Best regards,
Vlado