Avoid this game.
The game itself could have been good, but due to multiple bugs and very bad coding the game is close to unplayable.
First of all the game have severe memory leaks that will make the game slow down to a crawl or crash as your cities grow in size. This problem was first noticed at release and have not been fixed niether by the developers nor the rather enthuiastic fanbase of modders. This coupled with the games inability to use more than a single processor bottlenecks any gains from having a good gaming rig.
Second of all the game is allergic to Windows 64-bit systems. When the game came out this was not much of a problem. Nowadays however this means most new computer cannot play the game without errors. By now the developers have ceased any and all support for the game so don't expect any help there. Perhaps the modding community can fix this but it is highly unlikely and in my eyes a waste of time on a failed and abandoned game.
Put your money on a more deserving title.