To enter the BIOS just hit F2 when the system starts up. The ASRock Z68 Extreme4 uses a the newer UEFI BIOS. We of course started to see this type of BIOS on P67 motherboards. The UEFI BIOS uses a graphical user interface and enables the mouse so it is much easier to operate and is user-friendly. When you first get in to the BIOS it shows some information like the UEFI version, processor type, processor speed, total memory, and the memory channels.
The OC Tweaker tab is where you will find most of the settings for the CPU and memory. You can load both CPU and GPU OC settings along with changing many of the CPU features. There is a DRAM configuration menu where you can manually set the timings for your memory or load their XMP profile.
Moving down to voltage control you can set the voltages for the CPU Core, IGPU, DRAM, PCH, CPU PLL, VTT and VCCSA. Also you can set up to 3 user defaults. In the advanced tab you will find all of the settings for your CPU, North Bridge, South Bridge, Storage, Super IO, ACPI and USB.
There is a hardware monitor that will show you the CPU temperature, motherboard temperature, fan speeds, and Vcore voltages. You are also able to set fan speed settings. The boot tab has your typical boot settings. Finally in the Security tab you can set a Supervisor password and a User password.