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).
EDIT: Since I believe my card can handle better refresh rates and my monitor only supports 60hz I seem to face something called as 'screen tearing' which is the main reason for me deciding to replace the monitor. Below is the example for screen tearing: