I think it's pretty clear that Dalaran is the litmus test for any multiboxer setup, especially for those of us running 5 or more clients.

I can get around in Dalaran without any problems, even hearthing in, but it's noticeable that it's pushing a lot more through the system than anywhere out in the world.

Quad-core 3.0ghz, 8gig ram, 64vista, nvidia 9800gtx card here.

I don't see how it would be possible really to run Dalaran well inside a 32it OS, given the memory limitations.