New Dual-Boxing Setup for Classic WoW

[Apatheist]

Tried to run two Vanilla Clients and yes it works, but it's very laggy. And I think that Classic will come with updated graphics.

You can tweak the classic client a lot to improve performance. Check out this thread.

Reducing things like particle density and view distance below the minimum available via the client has a huge impact.

I know Activision says they're going to tinker with the API but they've said they will not be updating graphics. During Activisioncon they stated they would be recreating the classic models and textures as faithfully as possible so I imagine trying out the available private server client will give you a fairly sound comparison.