The Gigabyte EP45T-DS3R uses the Award BIOS, which I have used many times. It is set up with a main page and submenus for navigation.
The MB Intelligent Tweaker (M.I.T) page contains all relevant overclocking settings. It is quite a long page, but it is the only page you will need to navigate to when overclocking. There are lots of overclocking tweaks here, along with the basics. The only thing missing is the capability of independently setting memory speed, it is directly tied to the FSB, and adjusted with strapping and memory dividers.
The Standard CMOS submenu contains date/time, and drives that are recognized by the system.
The Advanced BIOS Features page has boot disk priority and boot order, and settings to enable or disable various devices around the motherboard. Of special interest is CPU Advanced Halt (C1E), and Intel Enhanced SpeedStep (EIST), both of which are required to operate Dynamic Energy Saver Advanced. I recommend disabling both when overclocking or benchmarking, EIST works by dropping the CPU to the lowest multiplier, so CPU-Z will give a lowered speed, and some benchmarks don't load the CPU enough to bring it out of the lowered state. You can also disable the POST splash screen here.
The Advanced Peripherals submenu has the settings for most of the rest of the items on the motherboard, USB, LAN, 1394. The PC Health page has voltages, temps, and settings for motherboard warning alarms.
Finally, the Security Chip submenu is where you enable the Ultra TPM security utility.