I admit I'm posting this because I'm too lazy to experiment, figured it was worth a try! I'll pop in with my results later in the week if I remember. My G5's backside fan (that little blower by the hard drive bay) wasn't working that well, and was allowing the memory controller to get too hot so I yanked the fan out and stuck a regular 80mm in its place. This has been working great, but out of concern I left the old fan hanging around next to the video card. Does anyone know if running a G5 without a particular fan plugged in will cause the thermal panic mode? If so I'll just.. find another idea I guess, but I'd love to just get rid of it since the fan is clearly triggered by SATA activity and has a stupid noisy motor.