I had a similar problem as in this posting: http://www.computing.net/answers/ha...
My config: 1x SyncMaster SA300, 1x SyncMaster SA350 on ATI Radeon HD 5450
Problem: the second monitor could not be configured to run with 60 Hz, only 29 Hz or 30 Hz; thus a very ugly and bad picture.
Solution: in the Catalyst Control Center; my VGA Displays; Properties (VGA Display); Monitor Attributes: just had to uncheck the "Use Extended Display Identification Data (EDID) or driver defaults", click apply, chose max refresh rate = 60 Hz, and problem solved.
I recon it could be helpful to somebody.
Kind regards, Charles