i was about to buy new 120hz monitor for gaming and keep my old one for browsing watching videos etc while gaming, but i read somewhere that probably 120hz and 60hz monitors wont run same time, since GPU will give only one signal either 60 or 120 so i want to confirm it before i buy one
That is not true from what I recall. You can utilize both, at least with Nvidia cards, and I don't know why it would be different for AMD. You couldn't run games across both monitors, but I don't think you'd want to do that anyways. I also found 3D Vision was a little temperamental in that configuration.