New video card. Cant use all memory slots

[Nissanspecv04]

Ive been running a 550ti with 16gigs of corsairs vengeance ram for a little over a year now. I decided to upgrade my video card. Went with a 7950 w/boost and since then, I have been unable to use all 16 gigs of ram(4x4GB). I can use any combination of memory sticks to have 8GB so I know each stick of memory works. I have tried each stick in each slot on the mobo as well. Boots fine. I figured the mobo was going bad so I replaced it with a MSI z77a-g45 board. Same issue.

I have updated the bios and even tried other ram(same kind from a friend). The machine wont boot at all. I have to reset the cmos and just use one stick to get it booted up again. Ive tried searching google but I just end up with video card comparisons, and buying ram suggestions. Any ideas?

 

[-RockMan-]

Crucial Ballistix Sport 8GB 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model BLS8G3D1609DS1S00 - Newegg.com

MSI prefers crucial for your new motherboard, but to be sure of that call them up and ask.
You could also ask them, if you might need to do a bios update to fix that minor issue.