3gb on a gt440 is like paving a street with gold, it is a waste and provides little improvement. A gtx 550 ti will be better as it has much better bandwidth and a stronger gpu than the gt440. The gt440 and the gt430 are crap cards and nvidia is only losing money on them by making them in the first place. The 6850 is ok card but drivers are not ati/amd's strong point and for 3d apps none of these cards are a proper chose but if funds are limited and gaming is not negotiable then settle with the 550ti. The gtx580 is a good card but more and more are having issues lately.