Youtube video's are not reliable sources of information. I looked at a couple of the ones you provided, no FRAPS counter, no way of proving that video was made on that hardware. If you want reliable info, look on review sites.
Think what you want to think. I won't pretend to know what people's motivations are, but I'm wondering what yours are for making this thread. But, I'm sorry, I'm not ready to claim a well known tech site like AnandTech are liars.. Sorry, thats just not happening.
I have seen videos claiming max settings at 1080p, 60+ FPS on hardware that is entirely inadequate (think it was an FX-4100, GTX550 and 4GB of 1333mhz RAM). There are plenty of people online who will claim uber performance for cheap, and show off these video's as "proof".
Lets just say that gameplay videos on Youtube (un-verified no less, you cant see any FRAPS counter or be assured of actual hardware used) cant be trusted over reputable review sites.
Do you think this card can run the latest games at 1600x900 high settings then?
back to my statement, it depends on the specific game, and if anti aliasing is on or not. at 1600x900 on high though, the 7770 should be more then enough I would assume. Anti aliasing basically almost effectively kills at least 10+ fps in general when settings are maxed.