Right but he says he intends to keep this card for 3 years and not upgrade. In that case think about BF3 expansions, all the upcoming Dirt games on Ego engine, Crysis 3, and newer games with tessellation. GTX670 will mop the floor with HD7850 in those types of games.
In Crysis 2, GTX670 is
69% faster than an HD7850 at 4xMSAA 1080P. In Batman AC, GTX670 is
66% faster with 8AA. That's remarkable. We can sit here and argue that those games are "NV-biased" which is a moot point since there most likely will be more Batman games, more Crysis games and more games in the future with tessellation.
Now take a look at
world's first MMO with tessellation (as far as I am aware).
Unless you think tessellation is a fad, things are only going to get worse for 7850 in 12 months. No amount of overclocking will help since GCN tessellation units are 1 generation behind Kepler. My prediction is when Crysis 3 ships next year, HD7850 will fall flat on its face.