Running at 84 fps on wow and its at 405 mhz, Do you know anything that could be conflicting with a Gtx graphics card ? i tried to go everything asus so this wouldnt happen haha
When you alt tab out to your desktop the cards frequencies will drop, thats normal.
From the looks of things you have a driver issue or some software issue. Again the game is CPU limited, and your overclock may be a problem. Try resetting the CPU to stock then testing, then overclock the CPU and stress test with prime95.
I just reset my i7 to stock then OC'd, and now get a core failing a test after 3 tests, so something went wrong there. have to dive into that more.
WoW is just one of those weird games where having more CPU muscle helps with the smoothness of the game, although a powerful GPU makes it look good(for an mmo) with all the eye candy maxed out.
EDIT: Do try the clean install option.. download the latest driver again and hit custom instead of express and hit clean install. Then uninstall any Overclocking software you might have, LIKE asus gamerOSD, or any other ASUS utilities for your GPU.