My GPU fans start up at full speed (even before POST) and remain at full speed all the time. In GPU Tweak III, the fan speed RPM is reading fine, but I can't control the speed in any way. I've read through similar posts with fan speed problems and followed as many troubleshooting step as I could find: Driver update, clean drivers with DDU then fresh install, BIOS update, BIOS rollback, checked the physical condition of fans and wires (fans run with proper speed control using a different PWM header on the motherboard). At this point, I believe the fan controller on the GPU board is defective. Does anybody have any suggestions?