Problem with brightness controls

[Colin Buttimer]

I've been suffering a problem with screen brightness controls and would be
grateful for advice. I have a 15" AlBook which is generally a pleasure to
use. However, using the brightness controls to make the screen either
brighter or dimmer causes the whole system to become sluggish and the
beachball to appear intermittently. This can last a minute or quite
significantly more and given that I quite frequently turn adjust the screen
this is quite annoying. I've tried turning on the automatic screen
adjustment but this doesn't do the job satisfactorily for me. I'm running
10.3.3 and have the backlit keyboard. Does anybody have any suggestions for
remedial action? Thanks in advance.

All the best, Colin.