According to the hubby, we've got the best video card that can be put in a laptop and we don't have any trouble running other graphic-intensive games like diabolo or war craft - and it seems to be unpredictable. At first I thought it just ran slow when there was fire or smoke or clouds, now I notice that it runs slow a lot more randomly than that :)

(I suppose that's what I get for buying the $3 version from the kiosk by the bus stop)