I'm using x64 vista and I just got my x1900gt today, I thought I'd be able to overclock it with ati overdrive but I dont see it in the catalyst, I used atitool and ati tray tools back when I had xp, it's just to much of hassle to disable driver signing that its not even worth ocing my video cards anymore. Does anyone know of any signed utilities for overclocking an x1900gt?