Dual Monitors Display - Not Working

[chhuong]

Dual monitors have been working fine up until 10.8.5. It is not working now with OSX 10.9 Mavericks. I have an ati Sapphire 4870 with dual DVI. I'm using DVI for both, and dual displays works up until the mavericks desktop appears. Once that happens the second display goes blank. When i go to display settings it thinks the second monitor is connected through vga. But it cannot detect that second monitor at all. Any help would be appreciated. I have done searches and see multiple issues with the dual monitor setup.

Thanks,

 

[water_cooling_man]

Dual monitors have been working fine up until 10.8.5. It is not working now with OSX 10.9 Mavericks. I have an ati Sapphire 4870 with dual DVI. I'm using DVI for both, and dual displays works up until the mavericks desktop appears. Once that happens the second display goes blank. When i go to display settings it thinks the second monitor is connected through vga. But it cannot detect that second monitor at all. Any help would be appreciated. I have done searches and see multiple issues with the dual monitor setup.

Thanks,

Hey chhuong,

Have you had any success on this yet? And did you have to do anything special to get your dual monitors working up until 10.8.5?

I have an ATI Sapphire 4870 512MB with dual DVI that I’m trying to get working with 10.9.2. I’m using DVI to HDMI adapters for both 1920x1200 displays. I have not had it working with prior versions.

Like your situation, the dual displays work up until the Mavericks desktop appears. I can use the "Gather Monitors" from OS X System Preferences to "arrange" the monitors, but monitor 2 never lights up (other than during the boot process).
I'm using the main x16 slot and PEG setting in the BIOS.

I installed 10.9.2 as a new install on a Gigabyte GA-EP45-UD3P using EasyBeast and no DSDT. Everything works fine.
The 4870 has worked perfectly from the start (on one monitor) with QE/CI. To try to get monitor #2 to work, I installed "QE/CI Exotic Patch for Mavericks 10.9.2" by Sascha_77 from another forum.

Any input you can provide would be appreciated.

Thanks!