There are many CPUs in the market and each is trying to compete with the other as far as speed and other performance criteria are concerned. The more the speed the CPU can execute more instructions per second thus making your applications run faster and better. However, it is not possible to change the CPU to a new CPU as soon as your new application demands for a higher speed CPU. The answer to this is over clocking the CPU.

Overclocking the CPU is nothing but improving the speed of the existing CPU without changing or upgrading the CPU itself. This can result in the maximization of the performance from the existing CPU which is a cheaper solution to changing the entire CPU.

The process of overclocking in many of the PCs is very simple. You can change the one or two jumpers available inside the motherboard and your CPU can be made to operate at a higher clock speed. However, overclocking introduces problems which try to block the CPU from performing at more than the normal speeds. Overclocking may not be a successful technique, and it requires some engineering to make it successful, as we will see shortly.

Limitation to overclocking the CPU:

1) Some CPUs which are already running at their maximum clock speed may not be amenable to over clocking. The AMD and the Cyrix CPUs are already running at their rated speeds. Only the Intel CPUs may be amenable to overclocking. However, not all CPUs can over clock to more than twice their rated speeds.

2) After you have overclocked the CPU by setting the jumpers on the motherboard, you may be in for an unpleasant surprise. Your machine may not work properly. The reason is that your motherboard may not be suitable at all for overclocking. Overclocking may introduce certain performance problems and your motherboard may not deliver clean signals, causing the CPU to malfunction.

3) Motherboard clock speeds present further limitations in the path of overclocking. If your Motherboard is running at higher than the rated speed it may cause problems with over clocking. Therefore, it is necessary to understand the clock speed limits and multipliers for your motherboard.

4) The CPU power supply can also cause a problem while overclocking. You might have to increase the voltage of your CPU power supply in order to support the CPU over clocking.

5) Internal Ram memories can also cause problems in overclocking, especially when the bus speeds exceed their rated speeds. You will require a higher speed memory to match with the higher speed of the CPU and the bus.

6) After overclocking the CPU it draws more current, causing the CPU to overheat. Hence, the CPU should never be over clocked unless proper care is taken to install better heatsink /fan assembly.

Process of Overclocking:

Step 1

The internal clock of the CPU runs at a different speed than the external clock. The external clock runs at a slower speed than the CPU clock speed. It is the speed at which the cache and the main memory run. When divided by two it gives the speed of the CPU.
The speed of the memory and the cache memory is known as the front-end bus speed.

You can change the front-end  bus speed to a higher level either by changing the jumper settings inside the motherboard or changing the bus speed through the CMOS setup. In modern motherboards it is the CMOS setup that is used to change the Bus speed to a higher level. For example, a 60 Mhz bus speed could be changed to a 66 Mhz bus speed, or to the 75 Mhz bus speed. The best method is to change first to 66 Mhz and see whether the Machine is working fine. If the PC functions properly than go  for the next level or else revert the settings to the previous speed.

Step 2.

You can change the multiplier of the CPU to increase the CPU bus speed. However, changing the multiplier is not resorted to, as CPU sold in market already uses higher multiplier.
 
The CPU supports the following multipliers :  x1.5 , x2, x2.5, x3. etc. depending on the CPU type. The CPU speed can be calculated by multiplying the front end bus speed by the multiplier. For example, multiplying 60 Mhz bus speed by 2 , we get the CPU speed as 120 MHz.

However, the CPU is already run in higher multiplier mode, hence, changing the Front end bus speed remains as the only alternative.

Step 3.

After the front end bus speed is increased, the PC should not be started immediately, without following the steps 3 and 4. This may result in the malfunctioning of the PC. The first thing to do is to increase the voltage of the CPU. This can be done by setting the supply voltage jumper settings on your motherboard, by referring to the motherboard’s manual.

Step 4.

Increasing  the voltage of the CPU will cause  heating of the CPU. This will result in the PC to malfunction. Hence, you will have to increase the heat sink capacity of the CPU. Proper hear sink / fan combination with higher rating can save the CPU from damage by overclocking.

If overclocking is done properly than it could benefit you. Care has to be taken while overclocking and proper instructions have to be followed. Overclocking could be a good solution to run applications which require higher speed, avoiding the costly option of upgrading the CPU.