either you have vsync on which limits your fps to 60 and you are sitting comfortable at steady 60fps most of the time, or your cpu is bottlenecking the card in these games at the graphic settings you are using. If you increase the in-game settings (details, AA, AF, etc) the load should go up. (thou the fps might also come down some if you over do it).
Anyways if the cpu is holding you back, try overclocking it.
i should also mention that i have a prolbme while playing Tera Rising too. The GPU usage is at 30% but when i turn off the UI interface the GPU usage rises and the ingame FPS double.
UI : http://prntscr.com/rwcjb
no UI: http://prntscr.com/rwcdm
I would go with the XFX model. You get strong components in that unit then you do with the ANTEC unit regardless if they both have Seasonic parts in which case they are not the ANTEC unit is using FSP oem parts which FSP is a good brand of power supplies I just know you get the better unit with the XFX unit. 80 plus is broken into categories