780i ftw mem issue

Hi guys!
I just installed my 780i ftw.
To start with i installed vista the mobo bareboned so that if it was rma it would make it alot easier to send it back. Everything worked perfectly.
Now i have installed all the components and found that the mobo refuses to run both my corsair cm2x2048-6400c5DHX sticks at the same time.
I've tested both sticks seperatly in all the ports they both work.
The error is the instant FF code.

Ive checked all the mem settings in the bios and they are all stock. (
I got my e6600 @ 3.6ghz). but that doesn't matter cuz it's the same at stock clocks.

And i have googled so much my eyes start to hurt!
plz help guys.

ALMS

Its the board RMA that shit