On my gb77-udh5 i use the hd4000 dvi for 1 LCD and on my 58x0 i use 1 dvi to vga for an older vga aoc LCD and 1 newer acer lcd on dvi. 3 monitors on various resolutions. Never above 1680 x 1080" though.
Mountain lion, ivy, macmini, All works apart from egen closing, it reboots after shut...