Dual Monitors and Internet Explorer

Does anyone else have problems with preformance problems with Vista Ultimate
while running dual monitors?
Everything runs great on this system, but as soon as I try to play WoW, it
stutters and comes to a grinding halt until I set everything into windowed
mode so everything is tiny.
I know the obvious answer is, turn off the other monitor...well I shouldn't
have to.
I even went so far as to install a second PCI E card on the other slot to if
that helped, which it did, ever so slightly.
Any ideas? I'm running a 4600+ x2 processor, and a EVGA 7600 GT paired with
a BFG 6600 GT.

Also, anyone notice a memory leak with IE? I can browse fine for awhile, but
if I keep the same window open for too long, and keep opening other tabs,
eventually I can no longer open other tabs.
What's wierd is that the Task Manager will sometimes show several different
instances of IE open, as well as the crash detection deal with the same
number of copies.

Any help would be great!

And does it seem like IE