Try plugging your display into this card.
im gonna do this next, but then again, i always leave my miners headless and control them using TeamVIewer.
Dummy plug tricks card into thinking it's not running headless. There are guides around if you Google... something like "dummy plug GPU Bitcoin" (w/o ") should work. Basically just putting a couple resistors in DVI/VGA holes.
Some configs have trouble utilizing all graphics cards headless, where driver downclocks GPU as if it's idling, even at full load.