I have a TV which supports 1080P at 120Hz and every once and awhile, I see lines (noise) go across the screen. This does not happen at 60Hz or 24Hz, just at 120Hz.
I have a GTX 760 with the 358.16-2.1 driver on Arch Linux using GDM/gnome.
I’m personally thinking that I don’t need 120Hz, but thought I’d report incase it’s a bug with the drivers. From my testing, it’s not the TV as I hooked up a computer running a GTX 970 with OS X on it and I don’t see these lines.