Are you talking about galactic conquest? Because on the full 70 planet scenario, the GC map lags so bad... But it does get a lot better as the game goes on.
Yeah, it chugs like a choochoo train. Tactical battles are noticeably slower too. I can usually push through some performance problems, but Republic at War's GC map was giving me headaches. The Empire at War's game engine has never been the best optimized unfortunately, regardless of what hardware you run it on.