Dual monitors sometimes not working at startup

[flmmkr]

I've searched the forums for the last few days and haven't come across this same issue. Other threads are about the second monitor never working, but mine is intermittent. Sometimes it works, sometimes it doesn't. I have the following components:

Asus Maximus V Extreme
Intel i7 3770K overclocked to 4.4GHz
EVGA Geforce GTXTitan Superclocked
2 x Dell U2913WM 29" Ultra Wide monitors (2560x1080)

Monitor #1 is connected to iGPU Thunderbolt/mini DP or DP.
Monitor #2 is connected to Titan DP.

Sometimes when I start or restart the computer the monitor connected to the Titan won't turn on. I've tried it with Monitor #1 connected to Thunderbolt/mDP and DP, but that didn't change anything. When this happens I have to disconnect Monitor #2 and connect it to the iGPU DP, let it get an image, then plug it back into the Titan DP. If I restart it's hit and miss whether Monitor #2 will work or not. Same with starting up after a shutdown. There doesn't seem to be any pattern to what causes it to work or not work.

In BIOS primary GPU is set to iGPU, memory is 64M, and discrete graphics is enabled.
Running OSX 10.8.4
GE-Yes
device-properties key in boot plist = 8800000001000000010000007c0000000200000002010c00d041030a000000000101060000027fff0400100000006d006f00640065006c0000001a000000496e74656c20484420477261706869637320343030302c0000004100410050004c002c00690067002d0070006c006100740066006f0072006d002d006900640000000800000005006201
Without that device-property key above OSX will not start.
DSDT patched with PJALM's repo patches Maximus V Extreme, Intel HD4000, and Generic Discrete Graphics (AMD/nVidia).
System definition is MacPro5,1

Aside from this issue and still not getting HDMI audio to work from either iGPU or Titan, everything graphics-wise seems to be working fine.

If I connect both monitors to the iGPU (one to TB/mDP and the other to DP) both monitors work every time, but I get mouse skipping. I think that's because the stated support for the iGPU is 1920x1080, but I'm running at 2560x1080. But this tells me it's not the monitors causing the problem.

Does anyone know why this intermittent issue occurs and what I could do to get both monitors to work 100% of the time? Is there a way to force OSX to initialize or use the 2nd display?

 

[flmmkr]

Through researching this problem more, I've made some changes to the configuration. I now have GraphicsEnabler=No, removed the device-properties injection in the boot.plist, and changed the system definition to iMac 12,2. I also created a new DSDT with patches in this order: PJALM Maximus V Extreme, PJALM Generic Discrete Graphics (AMD/nVidia), and then PJALM Intel HD4000. I applied then compiled between each patch. Doing all that got me HDMI audio when using a Mini DisplayPort to HDMI adapter. DisplayPort wasn't even showing in my audio devices list before making these changes. I don't get HDMI audio any other way from the HD4000 or Titan, and I think that's because my Titan is not in slot 1. I have it in slot 2 so that it's running at x16 (slot 1 runs at x8 when the other slots are occupied, but 2 runs at x16 all the time).

After doing all that I'm still having the issue of the monitor that's connected to the Titan not always activating on its own. I still need to connect it to one of the HD4000 ports and then back to the Titan to get it to work.