I never get over 30% CPU usage in MP or SP. I do get over 50% GPU usage in MP & SP. Quite often my GPU:2 has higher utilization for some reason.

MOBO: Intel BOXDP67BGB3
CPU: i7 3600k @4.0Ghz
Ram: G.SKILL Ripjaws X Series 8GB SdRam
GPS: X2 AMD Radeon HD 6970 2gb
OS: Win7 HP

I think removing the squealing sounds is a good idea as well!