More than 2 monitors

Jan 6, 2012
Intel Core i7 3.49 GHz
Mac Pro
Mobile Phone
Hi All,

Long time lurker, 1st time poster. I really need to get a 3rd monitor working on my hackintosh system.

I have just upgraded to mountain lion on my ga-z68xp-ud3r based system. It has been working really well with 2 monitors for some time. Initially with a Powercolor 6850 and now with a Gigabyte 640gt . I moved to the 640gt as it has native driver support in mountain lion, and I was hoping to be able to use both video cards at the same time. I wasn't able to get this to work. (triple monitors with the 6850 card would crash after a few minutes. triple monitors with the gt640 card just doesn't seem to work - 3rd monitor will operate during post, but switch off when the two other screens come on).

If I add another gt640 card to the system (giving me 2x gt640 cards), will it work automatically due to the driver support?

Note - there is a quirk with the ga-z68xp-ud3r mboard that requires PCIRootUID=1 in the boot options. No matter what other settings I change, I seem to need to leave this setting in place to successfully boot.

Thanks for your help.