So I just built my first rig and everything works perfectly BUT my Asus gtx670 DC2T gpu sags at one end. What can I do to fix this?? It makes me a little nervous and I don't want to permanently bend my pcb or my pci slot.
Either buy a fancy plastic shim, or built one yourself. Basically you just want to prop up the corner that's not supported at all. (And good for you for worrying - it could become an issue with time and vibration.)