I don't see anything wrong. The Heaven benchmark is a brute. Made that way on purpose. For comparison, the rig in my sig with 2 x GTX 660 OC cards averaged 42.9 FPS with Heaven settings at their max @ 1080p.
I'm using the 320.18 (release driver for 700 series) and have seen no issues thus far. Though a Google search I just did shows a couple articles claiming a small group of people say their GPU was damaged by that driver.