I was looking through the internet and I realized that both the Nvidia GTX660 and the Nvidia GTX680 had a memory of 2GB. This made me wonder that what is most important in a graphics card? Well, it was clearly not the memory as the 680 clearly has better performance than a 660. Then what is it? Also, I'm looking for a graphics card which is about $200-$230 (The 660 would be my choice, but I'm not aware if there are better ones out there so it's always good to ask) and will play current-gen and next-gen games at above High settings with playable fps. Thanks in advance to everyone!