As you might expect from a refresh part, there really aren't any massive differences to speak of when you compare R480 to its older brother - Functionally and feature set wise, the two are identical.

To put it simply, R480 is a tweaked version of the R423 core used to power the PCI Express version of ATI's initial X800 products. These tweaks serve the purpose of reducing heat and increasing clock speeds over its predecessor and, most importantly, avoiding some of the supply constraint issues we've seen in the past. The Radeon X800 line-up (X800 Pro aside), has picked up a far from illustrious reputation of being near vapourware, with X800 XT parts, the Platinum Edition in particular, being all but non-existent. Indeed, early indications are good that supply of these new R480 (and R430)-based parts are plentiful, with X850 products aplenty available for purchase. Whether this trend will continue with the AGP-based variants of these boards that come to market shortly remains to be seen of course, but the situation is looking decidedly more hopeful.