do you have the game already and are just asking so you don't have to install and waste time ? or are you asking becuase you want to buy it and don't want to waste money if it doesn't run smooth ?
i have the game and i have tried it on a G3 233, G4 450 and a G4 800 and it seemed to run fairly smooth on all of them. this is one of those " age of empires " type deals or more like one of those " sim city " deals and it doesn't have alot of stuff going on to make things slow down.
I have it (Mucho Macho edition) for my iBook G3900, 384 ram/ 32 vram. It runs ok.. but as your city grows it starts to bog down.
These types of games are very deceiving, the graphics may be nothing spectacular but there is a lot for the processor to keep up to pace with. Every citizen is doing a task, thinking, something, every building, industry, farm, hotel, etc are all keeping track of cost, maintinence and profits. and as the city grows there is a lot to keep track of so i would assume it slows down as it gets really cpu intensive with all those factors and more to keep track of.
the city i am on is approx 400 people and and you can account for every one on screen, you see them runing around going to work, church, hospital, caberet ;oP etc. I have even tried lowering the graphics setting but it doesn't make much difference. as I'm sure its not the graphics that slow it down.