i've read a bunch of reviews comparing the two and the performance seems about equal. the prices are within 20 dollars of eachother also.
i will have an i7 machine with 2 montiors, both at 1920x1200 or 1920x1080, but when gaming one would just have my desktop and the other would have the game.
will that give an advantage to the 4870 because of its extra memory?
and also, how do the noise levels and heat levels compare for both of them? with such a small performance gap, i'd probably just go for the cooler quieter one, assuming both performed equally for my needs.
The brands I reccomend are XFX, ASUS and Sapphire. I have a GTX 260 and I am very pleased with it. It is quiet, I can not hear it over the rest of my relatively quite pc. I have not tested GPU temperature, however always assumed that the Nvidia GTX range are cooler than ATI however this more an assumption. The performance difference is marginal, however the GTX 260 performs better slightly, most likely not even noticeable. Whatever you choose the GTX 260 or 4870 won't dissastisfy you they are both competent cards in today's games. Hope this helped