1ghz? 1.2ghz maybe?
Do you mean against a windoze PC? I would say maybe 1.2-1.4GHz, but thats IMO, I'm not sure...
EDIT:Oh..I get it now, yes a dual, maybe compared to a 1Ghz or 1.2GHz single, but having two procs. doesn't mean youll get twice the speed benefits.
Correct me if I'm wrong guys,
Any realistic estimate requires that you tell us what applications you wish to run. Applications are tuned to run on platforms, so if the application that you want to run is not tuned for a dual processor, performance on your system will be little better than for a single processor box running at the same speed. If you run the right OS and applications, your Mac will be a speed demon.
Mostly Hotline, photoshop, some P2P apps, and some games like Unreal Tournament 2003, Halo...