4870 can be OCed on 950 (Diamond cards) and it gets close to 280GTX performance
for higher resolutions and AA enabled, 4870 is much better(except crysis in twchpowerup review):
http://www.techpowerup.com/reviews/Point_Of_View/GeForce_GTX_260/9.html
http://www.techpowerup.com/reviews/Point_Of_View/GeForce_GTX_260/15.html
http://www.tomshardware.com/reviews/radeon-hd-4870,1964-9.html
techpowerup crysis test must be something wrong, ewery test i hawe seen has better score in crysis for 4870 than 260gtx
for higher resolutions and AA enabled, 4870 is much better(except crysis in twchpowerup review):
http://www.techpowerup.com/reviews/Point_Of_View/GeForce_GTX_260/9.html
http://www.techpowerup.com/reviews/Point_Of_View/GeForce_GTX_260/15.html
http://www.tomshardware.com/reviews/radeon-hd-4870,1964-9.html
techpowerup crysis test must be something wrong, ewery test i hawe seen has better score in crysis for 4870 than 260gtx