You still have a miss memory configuration if you're still not seeing nearly all of the 12 gigs.
As long as the latency is the same, ASUS recommends in this scenario that you put both sticks into the same bank. This way the first 4 gigs will pair-up in dual channel mode with the 8 gig stick, and the remaining 4 gigs of the 8 gig stick, gets put into single channel mode. Performance will still be there!
@@live-evil, You should still see nearly all the RAM, but you're not? I'm assuming this is still true!
I need the exact motherboard model to help you precisely? Located on the motherboard itself! The RAM that came with the system isn't all that important. Asus sold you the system with 12 Gigs of RAM, correct? There is a setting that could cause this in BIOS, or worse, you may have unmatched/ defective memory modules. Temporarily, you could move the two RAM sticks into separate banks. To do this, move the 8 gig stick to slot A1 and the 4 gig to B1. This will get you your 12 gigs of RAM, with a performance hit. Doing this will tell us that the modules are in fact miss matched or defective and of course, the motherboard could be defective too, unlikely!
Good luck!