What resolution are you running it at? 1920 x1600 or something less?
1920 x 1200
Will have a quick delve in the innards to see if any improvement possible.
Off the top of my head, I think that 1920 x 1200 is the highest.
N o t a
ETA Just had a delve and find that 1920 x 1200 is the max resolution.