I can't actually help with that, but I was wondering if it would help my old 9800Pro. I still have the stock (somewhat wimpy) HSF on it and was wondering if replacing the stock thermal compound with AS5 would help keep it a bit cooler. It doesn't have a temperature diode so I cant read the temperature, but I know from touching the heat sink (even at idle) that it gets pretty hot. Its no longer a gaming system so I'm trying to make it last as long as I can by reducing heat. I've already underclocked it to 300core/600mem and it still runs pretty hot.