Long time ago I was having problems with Asus mother board P6X58D-E seeing all my ram. First one got repaired and still didn't work. Sent it back and they sent me a new one. I checked the serial numbers. Just installed it and now I got all my 12 gigs in bios and Windows 7. Running a break in at the present. Prime 95 Torture Test 100% 65 deg c. 25 minutes so far. I don't think I will buy another Asus board, I have going through hell with this one.