I believe Civ4 epic is 660 turns long compared to the normal civ3 game of 540turns.I agree with ya that the civ4 normal game seems to fly by but epic is a pretty nice pace.I havent tried marathon yet .Gaizokubanou said:I loved civ2, liked civ3, and loving civ4. So I can't really even begin to relate to those who are disappointed with civ4 (other than those who are experiencing bugs... those can really ruin any game).
I just wish there was a pace between epic and marathon. Epic feels tad bit fast, while marathon feels awfully slow in the beginning.