Im not sure when it started, i noticed it just recently. I think R9 290x drivers is causing this, but i must do another windows reinstall to check this theory. Anyway its not a solution to not install a graphics card software.
edit1: i just loaded my cpu with prime 95 to 100% and wifi signal is good. Its pure gpu load that messes up my asus card connection.
edit2: ok i reinstalled windows. installed wifi drivers, firefox, flash player, torrent client and nothing more. connection is good and stable, download speed drops only for youtube traffic, i can see youtube preloading video very fast.