Hi, I'm lookin' for a graphics card for my friend, because he wants to upgrade from his crappy integrated graphics thats in his dell or whatever he has so he can play cod4. I noticed that the for the 8600gt and may also be true for other models, but that one has 256mb of memory with core clock at 620mhz while another had 512mb of memory and a core clock at 540mhz. My question is which would be better, i would think the first because that clock speed is faster, but i guess it could be the other cause of the memory, so if someone could clear this up for me, that would be very much appreciated. thanks in advance.