05-16-2014, 07:23 PM
I had a weird problem like that when I went to Mavericks and updated to a 2GB video card in my Mac Pro. When I plugged in my 30in Cinema Display into one of the dual link DVI ports and my 24in Acer into the other, the Acer was fine but the Cinema Display was at like 800x600. So I switched the ports that they were plugged into, and everything seems ok now. Not sure why, as supposedly both ports are the same.