70% load... but which wow was it? what res? was it alone on the cpu?

other question... do you run anti-virus / firewall software? could be eating cycles. considering disabling ONLY IF YOU HAVE A HARDWARE FIREWALL (couldn't stress that enough )

how many processes total are running on the box? (check task manager status bar)

try running a single wow, 800x600, and check the cpu load and fps. then move it to the other monitors... check to see if the cpu load or fps change.