I am running 4x2gb Kingston 800 ddr2 GA-EP45-D54P Mainboard Thermaltake Toughpower 750W 2x ASUS EAH4850 W/Crossfire I can access windows until i install the graphics drivers. Then i get BSOD. Go to Safe mode, uninstall the drivers and i can get in to windows again. Tried flashing mainboard bios to no avail. Tried disconnecting Crossfire to no avail. Tried taking one graphics card out to no avail. Tried Installing the drivers without the CCC software to no avail. The cards come with Glaciator fan sinks which work fine, keep the cards down to about 40C(102F) Am starting to think that the Mainboard just isn't compatible with these cards, although it does say that it is crossfirex enabled. I'm thinking it's not a Power supply problem as it has dedicated rails for the PCI-E connectors On the BSOD it says Attempt to reset the display driver and recover from timeout failed and in particular mentions ATIKMDAG.SYS Visited ATI website and this is what they say Symptoms: After installing the Catalyst display drivers and rebooting, the system will give a blue screen (BSoD) error referencing ATIKMDAG.SYS Cause: This issue is caused by using a motherboard with a chipset that is unsupported in Windows Vista Surely motherboards that are released now should be compatible with the graphics cards that are released now. I'm really running out of things to try, anyone care to help??