i have similar problems like "cfshelor" , at last with version 1.0 (Beta 5).
CPU usage was rising after 20 - 60 minutes between 3% - 24% (and then stays high)
This made me un instal the app, because its the only one witch heats my idle Mac up.
But I do like the idea, of sensor driven fans!!! Lots of thanks to the dev. Keep up the good work

Question: Is the fixed Fanspeed a minimum Speed, witch increase automatic, when temp. is rising? So Apples Fan Control is still working?
best regard
prologos