I'm running 5 clients on a Macbook Pro (2.3Ghz, 3Gig RAM, X1600). Cities get laggy and I have to keep the windows overlapped to make it run well.

What I should do is take some time and get my PC running again to offload a client or two and configure Synergy for it. That or convince my wife to let me buy a Mac Pro with 8 cores and gobs of ram. However, I think she would hit me with a nerf stick just for asking. :P