I originally posted this for someone else, but it serves as an OC 101:
This sort of info is Motherboard specific, but in most cases the menu's and settings are common. It breaks down like this:
- You CPU has a frequency
- Your Memory has a frequency
- Your PCI bus and all other sundry busses have a frequency
They are all related as (usually) one single clock genrator is used to get the original clock speed. The relationship is often like this, although there are ALWAYS exceptions:
CPU speed = Memory speed(before DDR or QDR) x Multiplier value.
PCI speed = Memory speed(before DDR or QDR) / 3 (or 4 or even 5, the goal speed is 33Mhz as PCI devices often hate high PCI bus speeds, such as hard discs=data coruption!!!)
AGP Speed = PCI speed x data rate(2x, 4x, 8x), so 2x = 66Mhz if the PCI is 33Mhz and so on
Multipliers are locked on P4 and can be changed on Athlons. Some motherboards allow the PCI clock to be locked into 33Mhz, this is good.
So, original speed of memory on a 400Mhz P4 is 100Mhz(400Mhz QDR) and the multiplier is 20, giving 2Ghz. To overclock, set the fsb to 110 and the CPU speed upon next boot will be 2.2Ghz (110x20).
Et Viola, your first overclock. Now I have simplified the process by a great margin and there is much more to learn. Do a google on 'overclocking' and you'll be on the road to getting all the info you need.
Hope that helps!