Ok, thanks a bunch for all these responses.
I have a question about the symilinking.
I simply have a copy of wow that I run specifically for multi boxing.
Would symlinking give me a performance improvement in that regard?
Or would that only be if I cared about separate settings for each client?

Finally, about the sound you suggest I turn it off at the device level?
What exactly do you mean by this and how does one go about doing so in windows 7?
What I take it to mean is go into device manager and disable the sound devices.
Is that what you mean by it?

Also, as a follow-up to the maxfpsbk post:
You have to set the maxfps as well as bk for it to work, I found out.
And the command to do it is:
/console set maxfpsbk 3
You had it right except for the set in there.