So I'm thinking either 320 or superclocked 320 or the 640. I'm planning to get a 24" 1920 x 1200 LCD soon. How hard is it to overclock a standard clocked 320 or 640 to the superclocked speed? Any need to upgrade the stock cooler? To my understanding the hardware is the same for the normal vs. superclocked cards, so it's just a software difference right? The machine will be used mostly for gaming.