Well, i'm trying to install a gigabyte r9-380x gpu and unfortunately having issues with atom-15.

Atom-15 is successful at patching the bios, but the pc will show the post screen for about half a second and then the monitor loses the signal and shows "No Vga Cable".
It's currently connected to an lcd that supports 15khz, didn't wanna take any risk with a crt.
Windows will not bootup as long as the vga cable is connected.
If connecting only a display port cable, windows will boot.
Tried with and without crtemudriver installed, no difference.
But if i start the pc with only display port connected, and then change to vga cable, i get a picture.
In vmm maker it shows two analog outputs, dvi-i and vga,
on the card there's only one analog output, dvi-i.
Here's a weird issue, if i have the modded bios installed, and try to enable edid emulation for dvi-i, that causes a signal loss every time i start Arcadeosd or vmmmaker, forcing me to reconnect the vga cable to get the signal back(This is an lcd, not a crt, i'm guessing on a crt it will just lose the signal for a brief moment.)
If the original bios is installed, this issue doesn't happen.
Regardless, The actual correct output in vmm maker is vga and not dvi-i.
I wanted to state all of that in the case it helps troubleshoot the issue with atom-15.
I am more than willing to try everything you'd like, Calamity, and i'm not afraid of bricking.
Unfortunately this is my second card in a row that has issues with atom-15, i would really like to try and get this one up and running.
I've included the original bios and modded.