Depends on the games as well. A vast majority of benchmarks (if not all of them) show the 280x at ~60-70 FPS average 1080p @ Ultra/highest AA, however, that's with an Intel CPU. The high single core performance does make a difference. Moreso than "in the future, games 'will' use more cores', which is pretty much true, but by the time that happens, and if AMD proceeds down this route, AMD's 8350 will still be considered sluggish.
I'm gonna say you'll get 40-50 FPS maxed out. 60-70.. perhaps 80, if you play with no AA. But the games you listed are titles that haven't been released yet, so there's no telling how well they're optimized