i dont think its cpu releated.. ive tried a couple of mods (all of them have advanced features implemented) and none of them "hangs' in a manor visa does (Amra runs fine). To be more precise, i sometimes have to wait 30s in beetween turn in the ancient era ?!?! (other mods usualy need 2-5s, depending on the events). It looks as tho the AI is looped in some point, the cpu usage stays on a decent level, but you have to wait a looong time for the next turn to start. Another thing i noticed is that sometimes when moving workers, the game hangs for a brief moment (5-10s), this is also not present nor in the vanilla game or other mods..
My spec are:
Athlon X2 3800 running @ 2500Mhz, 2 GB RAM, Radeon 9600 Pro..
cheers