PC Assembly - Installing the processor

The processor

The processor is the computer's key integrated circuit which performs the main calculations. Processors come in various formats which can be grouped into two families:

  • Socket processors
  • Slot processors

ZIF socket

When installing a processor of the ZIF Socket (Zero Insertion Force) type, make sure the small lever on the side of the socket is raised, then gently insert the processor, making sure the "alignment marking" on one corner of the processor lines up with the corresponding marking on the socket (consult your motherboard documentation for details).

Installing a processor on a ZIF socket

Finally just bring down the lever and the processor is installed.


Installing a CPU into a Slot is just as easy: the single edge contact cartridge that comes with the processor must be installed first. The processor is simply inserted into the slot, just like an expansion card (it only fits in one way).

Installing an active heat sink

ZIF socket processors need a heat sink as well as a fan, these items don't always come with the processor. Both items usually come together in a single unit known as an "active heat sink".

Active heat sink

Without a heat sink, the processor will overheat in a couple of seconds after the power has been switched on.

We recommend applying a thin layer of thermal paste (silicon compound) on the surface of the processor that comes into contact with the heat sink, this will increase the contact surface area between the processor and the heat sink improving heat transfer from the processor. Most active heat sinks already come with a thin layer of thermal paste, so you may not need to apply more.

Click one of the heat sink clips onto the nub on the ZIF socket, then gently click the second one into place. The heat sink must be centered correctly and make contact with the entire surface of the processor. It is very important to observe the orientation of the heatsink when installing: the step on the underside of the heat sink should be level with the protruding edge of the socket. Be careful not to apply too much force as the central part of the processor (silicon) is fragile and the slightest crack will cause irreparable damage.

Finally, connect the fan power cable to the designated power connector on the motherboard. It is a good idea to arrange the fan power cable so that it will not interfere with the fan's rotating blades.

There are other alternatives to active heat sinks, which some consider noisy:

  • Phase-change coolers: very effective but expensive.
  • Peltier effect coolers: silent but unstable.
  • Water cooling kits: stable, efficient and silent. Water cooling kit comprise of a water reservoir, a pump, a heat exchanger and a waterblock which absorbs the heat from the processor.

There are also software solutions which deactivate unused processor instructions in order to gain a couple of degrees.


On some older motherboards processor speed is set with the use of jumpers.

Newer "jumperless" motherboards automatically detect the processor speed and allow for the speed to be modified using the BIOS. The principle is the same for both types and consists in defining a frequency for the data bus of the motherboard (called FSB, for Front Side Bus) as well as a coefficient which is used to multiply the processor speed.


Jumpers are small pieces of metal covered with plastic and are used to allow electricity to pass through form one pin to another, they work just like switches.

N.B. If you do not want to manually set the processor speed and wish to use the default processor speed you can skip this section.

Jumper diagram

There are two types of jumpers used to set processor speed:

  • Jumpers that set the processor speed.
  • Jumpers that set the processor voltage.

The processor speed is obtained the internal frequency of the motherboard (or more exactly to that of its data bus, the FSB) multiplied by a coefficient.. Older motherboards have jumpers for setting the internal board speed and jumpers for setting setting the multiplying coefficient.

The jumper settings and their location on the motherboard are set out in the manual for your motherboard. We recommend doing this so as to have the highest possible speed for the motherboard, then setting the processor speed multiplier at the ideal speed.

Then finally the CPU voltage must be set using jumpers. Generally the following voltages are possible: 3.3V, 3.45V (typical voltage for most processors) and 3.6V.

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