How can I make Blender put less strain on my CPU? I am using GPU rendering and my CPU is really bottlenecking blender down to only 50% of max GPU performance, while blender is taking up more than 90% of my CPU usage. How can I put less strain on my CPU so it will stop bottlenecking my GPU?
If 90% of CPU load bothers you, ie its not comfortable to work with other programs, you can set priority to the Blender by Task Manager.

Press Ctrl+Shift+Esc to launch Task Manager.

Prior Windows 10, right click on Blender process->Set Priority->Low. In the Windows 10 select details tab, and again right click on Blender process->Set Priority->Low