Well...sounds like you have everything pretty well geared for speed & your ram is definately NOT an issue.
I have a 128mb 6600GT & 1.5gb Ram, however..my nVidia drivers are NOT WHQL.
I guess it all depends on your perspective & what YOU class as slow ie:"Vue windows are quite slow when refreshing, and it's pretty tough to do precision positioning".
Something tells me working on a machine like yours would be "WAY" quick for me.
Either way..it's sounds like something your going to have to learn to live with..unless e-on release an update that remedies the issue.
I hear Vue will be working with C4D soon & C4D has working 64 bit versions. It's already speedy on the 32 bit platform. I'd love to see how quick it(C4D) runs on a beasty 64 bit system.

It's a shame stupidity isn't painful.