To enter the BIOS with the AS45GTR, you use the normal command, "DEL". Once you get into the BIOS, this is the first thing you will see. It basically helps you get where you want to go. Also it allows you to set a user password, load your optimized defaults/fail safe defaults etc.
This is the Standard CMOS features tab. Here you can auto detect or manually detect all your IDE devices. It displays basic information about your memory and this tab is also for setting up features like the time, date etc.
Above you can see a snapshot of the Advanced BIOS features tab. Here you have options for your CPU cache, setting up the way you want your computer to boot (HDD first, CDROM first etc.) etc.
This section controls everything integrated on to your motherboard. It splits up into three sub-tabs, Onchip IDE devices, Onchip PCI devices and your SuperIO devices.
This sub-tab gives you detailed options for each IDE device you have on this motherboard. All your primary/secondary IDE PIO and UDMA settings are controlled here.
This is the second sub-tab for the Advanced Features tab. It covers everything Onboard PCI related. Above you can see things such as enabling/disabling USB 2.0/Controller, RAID, 1394 Firewire support, onboard sound etc.
The last sub-tab is the "Onboard SuperIO" tab. This controls most of your legacy ports such as Parallel port, game port etc. You also have IRQ options for those devices.
This tab controls everything related to power. You can enable/disable features like ACPI, suspend mode options, wake up events etc.
This tab controls your Plug and Play and PCI settings. IRQ resources can be found under this tab if you run into any conflicts.
This is the PC Health tab. Here you can find information on all your voltages and temperatures. You can also set a shutdown temperature, which can prevent your CPU from burning up if it reaches high temperatures.
This is the moment all you overclockers have been waiting for. This is the Frequency/Voltage tab where all the overclocking wonders happen. Shuttle has done a good job on including all the features you will need. It supports FSB speeds of up to 200MHz, you have several DRAM ratios (1:1, 1:2 etc.)
At first, when I was looking through this section of the BIOS, I saw this board has support for up to 1.85v VCore. But when I looked again, I saw that the Shuttle AS45GTR has an option to set your VCore up to 2.40v! Of course no one should dare setting their VCore that high unless they have substantial cooling (Phase cooling, water cooling etc.)