Essential: -

It should meet your requirement in terms of Resolution, refresh rate and video memory.

 For better Playback in Video/game it should support max. Resolution, refresh rate, and faster memory like edo, bedo, sgram or other

See it for further Video Ram Upgradation.

Also see it for Compatibility with Motherboard.

Max resolution, refresh rate, memory type, hardware driver compatibility is directly responsible for better output on your monitor in terms of Video/games/graphics quality and depth.