Yeah both 1900 and 1950 XTX are in there creaming the GX2 big time (sorry didn't specify earlier).
So will the GX2 work with that PW5 Asus mobo? Reading forums on anandtech and it seems like it does, with the right BIOS version. I'm about to just get the ASUS P5N32-SLI SE Deluxe and not have to worry about it.
RIG: Core2Duo E6700 | ASUS P5W Deluxe | eVGA 7950GX2 | Corsair XMS2 2GB
WD Raptor 10K RPM 36GB | WD Caviar 200GB | Scythe Ninja | Logitech G15
Aerocool ExtremEngine 3T | OCZ GamerXStream 700W | Viewsonic 19\" VX922
Microsoft Intellimouse Optical Black (old school fo sho!)