I have not seen any tests, but the number of AI routines and such that t has to run through is far more stressfull than the graphics. Plus the RAM gets eaten up really fast. If you want to have really big armies I would reccomend a gig at least. My 2.8, 9600 PRO and gig of cas latency 3 RAM in 4 256 sticks works quite well until you hit 6k troops and if you are just looking at the ground the frame rate stays the same...