I just did a fresh install of Windows 8 x64 Professional last night and for some reason the UEFI firmware settings tile doesn't show up under troubleshoot > advanced options.
I'm pretty sure my motherboard supports UEFI but I don't know if there are certain settings I need to toggle or what. Spamming F12 while booting up gets me into the BIOS but Windows 8 boot time + SSD doesn't make it fun at all.
CPU - 3770K
GPU - Sapphire 7970
PSU - SeaSonic X 1050W Gold Motherboard - Gigabyte UD5H-WB
Hard Drives - 2x Samsung 830 256gb // Western Digital Black 600gb // SeaGate Barracuda 2TB
Case - HAFX
There's a possibility I didn't install into UEFI correctly. I created a bootable DVD from an ISO, selected the boot drive from BIOS UEFI, and installed into Windows 8 that way.