My CPU usage is around 25%, I have HT turned on so FAH is only using a single core.
I set the CPU to 4 threads / cores in folding at home advanced settings, and my folding power is at full.
I'm running 10450 (104, 1, 129)
Hmm, not sure really.
You could always specify the number of cores to use manually.
Right click F@H system tray icon -> Advanced Control -> Configure -> Slots -> edit on the CPU slot, then put 4 in place of the -1 under CPU.