Actualy i was just playing M2TW and i had settings on medium-high except grass wich i have on low. I then played a decent sized city battle and the lag wasnt very bad, It DID lag but nothing that detracted from the fun, the lag only picked up a bit when i had a huge melee brawl in a whole i had punched in the wall, so i must have misread the graphic card i had, must be the original one because my computer seems to be able to run M2TW fine.
...Although Firefox 3 page scrolling lags like a bit**, i dont have that problem with IE..