Got a new monitor....is this banding or what?

[The Mailman]

Hi, just bought a new monitor and i notice that during some movies and esp. when things are dark (ie. a dark grey; noticed from a forum background color) theres a lot of flickering or movement in the coloring, like the monitor cant keep the color stable

is this an optical illusion due to the refresh rate? lcd defect? big/small problem?

thanks in advance!