If your purpose is purely gaming, there is no point of going for Mac because many games are not available for Mac platform. Even though this trend is changing but you will only get the latest games slower than Windows version. Anyway it also depends on what type of games you play. If its the latest FPS, RPG or RTS type of games you will have problems with the graphics card in the iMac but if its just Sims type of games (not graphically intensive), you'll have no problem.