asus r9 280x sometimes main display shows colored lines on boot

[Lath]

Hi!

I have a strange problem with my PC, sometimes when it boots up windows my main display (asus r9 280x) shows black screen and colored vertical lines are fading into the black screen, like memory fault. The other screen on the hd3000 of the 2500k boots up normal, windows seems to boot up ok also. It's like 50-50% if it boots up ok or not. If the PC boots up ok, there is no problem with the card, everythink is normal! It's Win 8.1 64bit.

WTF?

Any ideas?

Thx! Máté

 

[popatim]

I would begin by swapping the cables between the two monitors just to make sure its a GPU problem and not a display one.