Why is GPU maxxed but only getting 45 FPS? (screenshots inside)

[sofakng]

CPU is only showing 50% though?

Also, if I check "Skip Dest. Alpha Pass" I gain a HUGE FPS boost and my GPU usage drops to about 50%, but of course the game (Super Mario Galaxy) has really bad shadows, etc.

EDIT: Also, if you check the task manager screenshot you see that every core is at about 50% so it seems like I'm bottlenecked by my GPU?