6850 is slower than 5850. So, going from GTX460 to 6850 is not worth at all, keep your card, buddy.
Thanks for the replies.
I don't have either of these cards yet. I currently have a 512mb 3870 that I'm moving to secondary PC, but it sounds like the $55 difference isn't worth it. I have my PC hooked up to a 720 TV, so I don't have much need of higher res in the foreseeable future.