Thanks for your help.
I went through all possible settings in the graphics driver, but nothing had a dramatic effect. I did however recalibrate the screen via Windows and the display itself, and things are starting to look better.
However, I'm still experiencing a performance issue when watching flash based videos on the web through a browser. The CPU is high, and videos stutter and lag. Not sure if this is a plugin, browser or driver issue, as all are up to date.