Mini DisplayPort is a compact version of the DisplayPort connector introduced by Apple in 2008. Mini DisplayPort is free to license, and in 2009 it was included in the official DisplayPort 1.2 spec. In 2011 Apple and Intel announced the Thunderbolt format, which used the same physical connector, but significantly different protocols.
Screen refresh rate is the number of times an image on any type of monitor or television is reconstructed per second. This is measured in hertz.. (Hz).
(Hz). For example, a TV with a refresh rate 60Hz, reconstructs the image you're seeing 60 times every second. Basically, the higher the refresh rate on a tv, the representation of motion will be smoother, and the image will flicker less.