Hello,
How did you get the installation to work properly? I have a GA-Z77mX-D3H TH and I can't get the USB drive to work. I'm booting on the USB, then I've got a message saying I can press a key if I want to add options and after 5 seconds, the computer restart. At first I've got a grey screen but couldn't pass through it and now it's just reboots and reboot.
Tried with the GTX 660 Ti in and plugged the DVI on it during the install did not work, same issue, tried forcing the integrated graphics, same reboot, tried after removing the graphic card and still, just reboots. Also tried GraphicsEnabler=0, so far no luck.
Edit : ok, whatever, I went to the BIOS and I just used "Load Optimized Defaults" and I was able to load the installer. It's installing right now. I'm amazed because we have nearly the same setup. Same case (except I've got the ATX version, did not know there was an mATX). Nearly same graphic card and same processor.
Edit 2 : During the installation, the screen vanished to a plain grey with only the mouse. I though it was a freeze but actually it was just sort of a screensaver, I just had to move the mouse and the screen went back to the installation
Edit 3 : Hanged on first reboot, add to boot with -x option. Installing Multibeast right now.
Edit 4 : Ok, running solid while writing this words. I'm restoring my Time Machine backup. Audio is working (front panel and back), at least for the audio out jack. I'm getting some noise in my speakers if I put the volume to high but at least I've got sound. Display working properly too on DVI on the Geforce GTX 660 Ti (GraphicsEnabler=No but I read it has to be this way because the card is supported by 10.8).