Fan eating CPU

I just bought a new computer and everything runs fine but I've been noticing that after the case fan gets to a certain temp the fan starts whirring at full blast and all of a sudden the System process goes up to almost 99 CPU usage. So my question if this, does a case fan use the CPU to sense the temperature in the case and thus eats it away? And if so, is there a way I can disable that function and just have the fan be a full blast all the time?

>>1

I suspect you're mixing up the cause and effect.  Are you absolutely certain that the higher fanspeed is causing the increase in CPU?  It's much more likely that the spike in CPU usage is causing the fan's RPMs to ramp up.