i upgraded my dell 620 i3's psu from 300watts to 400watts then upgraded from galaxy nvdia geforce 9500gt to a galaxy nvdia geforce gt440 the 9500gt only was ddr2 and 1gb and even with me having 6gigs of ram for the max it added only 3844mb to its card now with my new card i got over 4gigs and its a ddr3 and all this made a big diffrince my computer is playing games fine