The DDR3 9600GT 1GB is a little bit faster than the GT240. The GT220 will be too slow to game with on a monitor that size. Just don't expect to be able to run those games on high settings with the gt240 or 9600GT. If you can get a GeForce 9800GT, Radeon HD 4770, 4830, 4850, GeForce 9800 GTX or Radeon HD 5750 (Listed in order of performance) I'd go with the highest you can afford. One other factor to consider is your power supply. What is it and do you have any power connectors (6 pin or 6+2 pin) for a PCI Express Card? Just my opinion, it comes down to how much you are willing to spend.