Well my mobo is a :asus p6x58d premium and my processor is a Intel i7 930 both are compatible with each other, and the reason I know they are dead is I called ASUS and I tested each stick of ram in each of the slots and it wouldn't boot from all the slots but the A1 (first blue which my mobo recommends) I could have two sticks of ram in A1 and B1 but it'll only recognize the one in A1. I ran scans and memory had to problems. The question is would 8gb single be better or see better performance then a 4gb single? I am only doing this temporarily till I get a new mobo. I think it shorted , that's why they died.