Quote Originally Posted by Chihaya View Post
dunno about the iMac part, but rest of the things looks beyond what is needed to run it on highest settings

http://na.finalfantasyxiv.com/benchmark/

Can try the benchmark, see what score you get before the whole installation
That benchmark program will be able to tell you not only if your computer can run the game, but how well you can run the game settings-wise.