Alienware m17xr3 and m290x

hello, i recently bought m290x for my alienware m17xr3. but i cannot get it to work.
i have unlocked a12 bios and set to peg in bios as the 7970m install guide.
when trying to start the laptop i get 8 beeps. my old video works fine, but i cant start this m290x.

any ideas? is it compatible or the problem is something else?

thanks in advance

Alienware m17xr3 and m290x