Not everyone is the same as you. I easily notice the difference between 80 and 120 FPS. Some people are more accustomed to it than others. I have spent what must be about 10 years playing Quake 3 competitively @ 120fps/120hz. Once your used to 100+ fps you start to notice these variations pretty...
I wonder if the 790 would sli with a 780 Ti?
Then I could use SLI when playing games that dont use more than 3gb vrsm and simply disconnect the 780ti when I need more vram
Are you using the skyn3t bios to increase voltage?
I dont think the voltage control in afterburner or precision X are working for me. If I add +75mv it wont even let me overclock an extra 10mhz. I havnt tried the skyn3t bios.
V-sync adds input lag. I used to be a competitive Quake 3 player so I am extremely sensitive to input lag and thus can't stand playing anything with v-sync enabled. 120hz monitor + high fps ftw :)