I've installed a new cooler with 4-pin fan on my Sapphire HD4850 and then set the Duty cycle min in the BIOS to 25% (to 45° C). Although the temp is at 38° C max the fan is always running at 100% (GPU-Z says 0% with ~1933rpm ). When I start CCC and switch to manual fan control it works (GPU-Z shows correct percentage) but switching back to Automatic results in 100% fan speed regardless of the temperature (<40° C). With the old Fan the pwn control was ok but why not with the new one???