So, I'm trying to put together a PC. I have an AMD 1090T (6 cores), and a gigabyte UD5 motherboard (the 890FX one). When I go to "Advanced BIOS Features", it only shows cores 2, 3, 4, 5. Where are the other 2?
Have you updated the BIOS to the latest version? That chip was released after the motherboard, so you will likely need to update to be able to properly use the newer CPU.