its because of your graphics card. just cause 2 is a very resource intensive game. you only have a 768mb card. you can't expect to play maxed graphics and maintain 60+ fps.
do you realize what you are saying?When I highly overclock this card it runs crysis maxed never dipping below 30 and even metro 2033 dx 11 very high with tesselation and 30+ fps.Just cause 2 keeps having weird slowdowns.whewn the fps drops from 40 to 30 the game looks like going into slow motion which is something I have not experienced in any game