GPU to CPU Load (100% CPU Usage)?

I was playing a game which was rather slow in my PC. When your GPU has reached its peaked it pes some of its load to the CPU. I found out that my CPU load while playing was only at 50% so my question is: Is there a way to pump it up to 100%? Any software, code, tweaks to make this happen? My CPU is a T2370. Intel GMA X3100 (It ain't that bad)... Thx.