When I was using my onboard graphics, Intel HD4600, I was able to set up a dual boot on my SSD with a legacy BIOS Windows 8.1 64-bit installation and legacy BIOS Fedora 20 64-bit installation.
I put in an AMD Radeon card and the Windows 8.1 partition works fine, but the Fedora partition stopped booting - occasionally I would see a page of garbled/corrupted graphics and then my monitor would go into standby and I would be forced to restart my computer.
I put in my Fedora Live USB to repair the installation, but the BIOS Live USB loader exhibits the same behavior (unable to display, display goes on standby). The UEFI Live USB loader however works fine (Fedora Live is able to load normally and the display works and all).
Does anybody have any ideas as to what could be causing this?
BIOS + Windows + Intel HD graphics = good
BIOS + Fedora + Intel HD graphics = good
BIOS + Fedora + Radeon graphics = no boot
UEFI + Fedora + Radeon graphics = good