Originally Posted by
BeardedJesus
The 60 or 120 stands for how many times per second that the screen is refreshed. Going from 60hz -120hz will result in a smoother experience in games as long as you have a strong enough GPU to push 120fps. You will also notice it when dragging items around on the desktop, it just feels nicer and more buttery
The blue cable you speak of is a VGA cable I think and can't be used when running 120hz, dual link DVI will be able to support the higher bandwidth at high resolutions like 1080p and so will a DisplayPort. Using the blue VGA cable with a DVI adapter will also not work.
Hope I helped clear some stuff up for you.