Graphics setting optimization

[Varunnagwekar]

Hi,
I have the following spec:
AMD 6000+ X2 Dual Core processor,
2GB DDR 2 RAM
ATI 4870 GFX card
24 inch BENQ monitor

My question is, since I have a weak cpu combined with a good graphic card, I would like to know what video/graphic settings in the latest games affect cpu and the graphic card respectively.
Meaning I want to ramp up the graphics full notch but only those settings which don't affect my CPU in any way.
I have found 100% CPU utilization in some games (like gears of war) and some drop in framerates, and I wanted to find out if there was something I could remedy this.

I hope I have explained my situation properly.

Thanks for the help in advance.