Greetings,Without getting into specifics. In general, a GPT formatted boot drive needs a UEFI compatible BIOS. Non boot drives (formatted GPT) don't need UEFI BIOS support.
Yes, and I was just updating my post.... Multi-boot?... as I said before. Some may or may not work. Its not definitive and is changing rapidly.
Is it possible to have GPT boot with this s775 motherboard? NoYou have an old motherboard with a legacy BIOS. You can only boot with a MBR partition table. A GPT boot requires newer UEFI BIOS hardware not available on the GA-EP43T-USB3.