XFX GeForce 7800 GTX 512 XXX Edition
 

In that preview article, I talked about the XFX GeForce 7800 GTX 512 XXX Edition graphics card. Today, it's time to take a closer look at that card as promised. Those three letters ('XXX') might already have your head in the gutter, but here's what XFX wants you to know about its XXX Edition cards.

'Products marked with the label XXX have a new level of graphics performance and experience. During selection of the components, the absolute top is being separated from the masses, including the GPU’s. During the production, only the best yield [top 10%] has been selected to go forward into the XXX production. During this extensive tuning process, the products are being pushed to the max and then made ready for the assembly process. This is why we have called this level of graphics cards eXtreme, eXtreme and eXtreme again, visualized into the ‘XXX’ logo. The three X’s stand for eXtreme overclocking, eXtreme performance and eXtreme cooling.'

http://www.bjorn3d.com/read.php?cID=855

It looks to me the 512MB cards are pretty maxed. The clock increases are very small just like with the x1800XT TOP.