Hedge your bets errr....trim that bush errm...leaf that thread alone and swan over here and take a gander at this-
When looking at 2 graphics cards that are identical, except one has more memory and the other one has a higher clock speed, wich would be a wiser investment, considering the user plays a lot of fps's and really doesnt have a large screen, but newer games are using more and more memory.
1GB Grotbags HD 4670 1746MHz GDDR3, GPU 750MHz
Or
512Mb Grotbags HD 4670 1746MHz GDDR3, GPU 800MHz