Now it's time to look at the BIOS. ASUS uses its trademark Award Tab BIOS as we like to refer to it as. Its appearance and colour scheme is identical to the reference BIOS Intel uses for its own desktop boards, but ASUS has a lot more tweaking options under its hood.
Usually we are greeted with the system info screen when entering the BIOS, however, the Rampage II Extreme goes straight to the Extreme Tweaker overclocking menu. Since this is an OC edition board, it's of no surprise.
BCLK Frequency: 100 - 500Mhz in 1MHz Increments
PCIE Frequency: 100 - 200Mhz in 1MHz Increments
UCLK Frequency: 1600 - 5600MHz in Various Increments
QPI Frequency: 4800/5866/6400Mhz
CPU Voltage: 0.85v to 2.1v in 0.00625v increments
CPU PLL Voltage: 1.8v to 2.5v in 0.02v increments
QPI/DRAM Voltage: 1.2 - 1.9v in 0.02v increments
IOH Voltage: 1.1 - 1.7v in 0.02v increments
IOH PCIE Voltage: 1.5 - 2.76v in 0.02v Increments
ICH Voltage: 1.1 - 1.7v in 0.02v increments
ICH PCIE Voltage: 1.5 - 2.76v in 0.02v Increments
DRAM Bus Voltage: 1.5 - 2.46v in 0.02v Increments
Overclocking on the Core i7 platform is a totally different feel; its like overlclocking the AMD K8 and K10 processors where you have a huge range of settings to play with and have to adjust them all in order to get anywhere. There's a lot more trial and error involved.
First, you need to adjust your base clock which is the FSB clock, the speed that the request queue inside the CPU runs at. You then have DRAM ratios to adjust the DRAM, which is pretty well normal. The two new strangers on the block are the QPI divider which is the link between the CPU and the External Northbridge and this must be kept in check to prevent any data loss and system instabilities. Lastly, there is the UNCORE divider. This is the speed of the actual on CPU Northbridge; this must be kept as close to default clock speeds as possible to prevent any abnormal CPU errors.
With a the little amount of time we get for overclocking here these days, we did manage to press the CPU to 3.4GHz using a 210MHz BCLK. Remember, though, the Core i7 uses a 133MHz BLCK, so this is quite impressive.
Important Editor Note: Our maximum overclocking result is the best result we managed in our limited time of testing the motherboard. Due to time constraints we weren't able to tweak the motherboard to the absolute maximum and find the highest possible FSB, as this could take days to find properly. We do however spend at least a few hours overclocking every motherboard to try and find the highest possible overclock in that time frame. You may or may not be able to overclock higher if you spend more time tweaking, or as new BIOS updates are released. "Burn-in" time might also come into play if you believe in that.