Affinity with one CPU = 100% of ressources

[zebulon]

Before starting, I should mention my processor is an Athlon 64 X2 3800+.

 

After reading here that Grim Fandango didn't like too much dual-core CPUs, I used some utility to set affinity to CPU0 only for the game executable.

 

GF now runs pretty well (I'm still in year 1), but it uses my CPU to 100% and makes it heat pretty quick, which in turn makes my main fan go faster.

 

Since the CPU load can't be justified by the amount of resources required by the game, can someone explain me how this happens? And how to make it stop?

 

Thanks for your help