what are you looking for in a graphics card eg; Core Speed, Memory or Memory Speed what one of these three do you look for and you must have or must you have all three of them
I also look at the number of pixel pipes, vertex shaders and bus width. An 800MHz core with 512MB GDDR3@1400MHz isn't that good if its only got 2 pixel pipes, a single vertex shader and 64bit memory bus.