The two values that determine the speed of the processor (frequency of the bus or clock and multiplier) are found on the motherboard. The method used to change them depends on the model of motherboard itself. There are several ways:
Using jumpers or microdips
Both the jumpers and the microdips act as switches which change the configuration of the motherboard and are, logically, located on it, so to change their position you have to open up the computer. Both have two positions: “on” and “off” or “close” and “open”.
The jumpers are small metal pins standing out perpendicularly from the motherboard. If they have a cap on them this means that they are in the “on” or “close” position (circuit closed). If they don’t, then they are “off” or “open” (open circuit).
The microdips serve the same purpose as the jumpers but in a different way. They are like a box with small pins, which may be in either of the two positions described above.
Each speed of the motherboard bus and the CPU multipliers has a different position from the jumpers, the colours of which might be black, blue, white, yellow or red, according to the manufacturer.
Once you have assigned the new speed of the motherboard bus using the jumpers, you then modify the CPU multiplier.
The configuration of the CPU multiplier is done in the same way as for the speed of the motherboard bus.
Recently, there have been many motherboards whose speeds can be configured using Bios, so you don’t have to open up the computer to change the speed, although you should bear in mind that the fact that these parameters are more accessible using BIOS rather than the jumpers does not mean to say that trying multiple combinations is any less harmful. Generally speaking, this option is to be found in the Chipset Features section.
Steps to follow to adjust frequencies using BIOS.
1) Switch on or restart the computer and, during the memory check, detection of hard disks and CPU phase, press the DEL key when the message "Press DEL to enter SETUP” appears on the bottom left-hand side.
2) In the blue computer Setup window (Bios), move onto the Bios Features Setup, CPU Soft Menu or similar option and press Enter.
3) Modify the CPU Host Bus Frequency, Ext. Clock (PCI) or similar option with Page Down until you find the motherboard bus speed you want (e.g. 112 Mhz for processors whose bus normally works at 100 Mhz).
4) In the CPU Core section: Multiple Bus Frequency, Multiplier factor or similar, modify the value of the CPU Multiplier (which can change from 2.0x up to 8).
5) Exit Bios saving the changes by pressing the F10 function key and answering the SAVE to CMOS and EXIT (Y/N)? message by pressing Y.
This is a mix of the above types. Some motherboards can be configured both by the jumpers and by bios, the second option being the one offering more configuration possibilities.
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