1. Unified Extensible Firmware Interface (UEFI) is a specification for a software program that connects a computer's firmware to its operating system (OS). UEFI is expected to eventually replace BIOS. Like BIOS, UEFI is installed at the time of manufacturing and is the first program that runs when a computer is turned on.
2. No, Optiplex 780 mini tower use normal(Old) Bios.
3. Yes, you don't need UEFI bios to run a GT 1030, All you need is a PCI Express 2.0/3.0.