Ok i have a Asus Crosshair II foumua board. i was using it with a gtx9800+ that card was starting to get really hot not to the point of over heating but close. so i figured id get a much new but mid range card that would run much cooler and quieter and have just as much power if not more.

so i got a asus gtx660 direct cu II card.

The board has 3 full length slots. 2 blue ones wired for 16x and 1 white one thats is 8x. if i install the 660 in either of the blue 16x the system powers on u get the normal beep code and then it just hard locks at the bios splash screen. if i install the card in the 8x slot though it post in and boots in to windows xp perfectly i can stress test and everything is runs fine games no problem just that it only runs a pcie 8x mode.

if i put the card in a way newer x570 board it has no issues in there.

the crosshair board has the newest bios update. the 660 didn't have the newest vbios but i updated to it although from what i can tell all it was for was to let u be able to use it with a uefi bios witch the crosshair don't have anyway.

the 9800gtx+ had no issue booting from the 16x.

so i don't seem like the video card or the board are bad i just can't get the 660 to run in the either of the 16x slots for some reason. i tired resetting the bios removing the battery everything i could think of.

i tired cleaning the 16x slots with contact cleaner and the pcie connector on the card with alcohol. pulled the cooler and replaced the thermal paste with fresh stuff the factory paste was hard as a rock.