sounds like the game or a setting and or driver...your system should be eatin this game up....
am running 2.2 amd athlon and 1gb vid card and 2 gb of ram or memory? at 800mhz...game runs fine ..although full armies can lag on MP....

am comp novice myself for most part buy am sorting out hardware finally...would look at upgradeing memorey if its slow or lacking....belive the higher the mhz on the memory the faster it gos...on hindsight passed up 2gbs of 1300+mhz for the 800...