GeForce GTX 260/280 versus Radeon HD 4850/4870
http://www.techspot.com/review/109-geforce-gtx-260-280-versus-radeon-4850-4870/

Gamers looking to purchase a new generation graphics card today have quite a few options available ranging in price from $180 to $450. Indeed, it’s a great time to upgrade.

Our preliminary testing shows that the GeForce GTX 280 is the most powerful graphics card money can buy you right now, but exactly how much more powerful is it than the Radeon HD 4870? Then there is the Radeon HD 4850 which is our value card of choice. And while we know it can beat the GeForce 9800 GTX hands down, how much slower is it than the GeForce GTX 260 exactly?