My Mac is a Mac Mini with 1.5 Ghz G4, 1 GByte RAM, 64 MB VRAM, 167 Mhz bus, and built in ATI Radeon 9200. I play with the music and ambient sounds off and the graphics set to low, with all the extra graphic bells and whistles off. I usually play at normal speed and normal map size. It slows down in the late game but not unbearably. I did play one game at large map size with 13 civs, which was unbearably slow towards the end, although I did that before I thought of turning off the sound. I am now playing a game at huge map size with only 7 civs. So far, at year 1862, it has still not slowed down. I will add that I am not a very demanding player when it comes to game speed so others may find what I consider okay to be really slow. In the current game, it takes about a half hour for a turn, but a good bit of that is me looking around the map and deciding what to do. I'll also add that this is only my thirteenth game so far.