How to Install a CPU

Guide to replacing a CPU, upgrade a CPU or installing a new CPU


This guide details how to install a CPU for a new PC build and assumes that you are fitting the CPU to a new motherboard prior to assembly within your PC case.

Installing an Intel Core 2 Duo processor will be detailed but note that the procedure for how to install a cpu will be very similar for other types of CPU.

Installing a CPU is much easier with your motherboard outside of your PC case on a stable, flat surface where you can easily see what you are doing and the board is properly supported on an anti-static mat.

Securing the heat-sink and fan assembly to your CPU will involve a fair amount of force and pressure and if your motherboard is not adequately supported you may bend the board and possibly damage the fragile PCB tracking or components.

E8400 Processor

It is possible though, if you are simply replacing a CPU, to install a CPU with the motherboard fitted inside your case – you just have to be a little more careful not to flex your board too much during fitment and accept that it is going to be a little tricky getting access etc.

How to install a CPU – Motherboard Preparation

For now all we need is your motherboard, processor and heat-sink / fan assembly, not forgetting our anti-static mat and wrist strap.

We strongly recommend the use of an anti-static mat and wrist strap. These are not very expensive to buy and will come in handy whenever you do an upgrade or work on your PC.

If you really insist on not using one then do at least ensure that you ground yourself by touching something that is connected to a good earth. Beware though – most warranties will not cover you if you do not take adequate anti-static precautions and zap that precious processor in not doing so!

So, ensure that your mat and wrist strap are connected to an earth point.

Place your motherboard on the mat, being careful not to touch any of the components unnecessarily, try to hold the board by the edges and place it carefully on the mat in front of you.

Identify where the processor socket is and you will see that the processor socket has a protective cover fitted as shown below:

Motherboard Plastic Processor Cover

Lift the securing lever and carefully remove the plastic protective cover.

Keep the cover safe in case you need to return the motherboard due to fault or failure.

How to Install a CPU – Processor Fitment

Next, carefully remove your CPU / Processor and heat-sink from its packaging. Be extremely careful with the pins on the bottom of your processor – they are so easy to bend and damage!

Ensure that you handle the processor by the edges as shown and be careful not to drop whilst handling. Look at the bottom of your processor. One corner should have a small gold triangle which you will need to line up with a similar mark or indicator on your motherboard socket.

Processor Corner ident

Offer up the processor to the socket and carefully lower it into the socket. Do not use force, it should offer no resistance and simply drop into place.

The processor should now be securely seated and the smallest amount of pressure will confirm this.

Do not force fitment or you will most certainly bend the pins and may well damage the motherboard as well.

You can watch a short video here giving you further guidance on the actual process of how to install a CPU.





Now that you are sure the processor is correctly seated you will need to close down the metal retainer lid and reseat the locking lever to hold it securely in place. The lever will require a small amount of force to re-locate it under the clip at the side of the socket. Here we have the processor securely installed in our motherboard.

Processor installed

How to Install a CPU – Heat-sink and Fan Installation

Okay, we haven’t finished yet – we need to provide a means of cooling our CPU.

Never, ever run a processor without its heat-sink. It will fry and die immediately. These things run at very high temperatures and need to have a very efficient heat-sink and fan installed to keep them cool.

Hopefully you have bought a retail processor which will come with the manufacturer’s recommended heat-sink and fan.

If not you will need to source your own heat-sink together with some thermal paste to fit to your processor.

Ok, now on to installing our retail heat-sink and fan assembly. The base of a retail heat-sink has a ready applied thermal paste, which will adhere to the top of the processor during fitment providing a good thermal path between the processor and heat-sink.

Base of heatsink

If not you will need to purchase or obtain some thermal paste which you apply to the top of the CPU prior to heat-sink fitment. A small pea size quantity of paste should be applied to the top of the processor and, using a piece of card, spread thinly and smoothly to cover the top of the CPU.

Arctic Silver thermal paste can be obtained easily and this smoothes out the tiny surface imperfections allowing for maximum heat transfer from processor to heat-sink / fan assembly.

Now, do not allow anything to come into contact with the thermal paste, including your fingers!

Note the four lugs at the bottom four corners of your retail heat-sink – these lugs will locate into holes on the motherboard and will lock into place to hold the heat-sink securely to the top of the processor. You now have to lock the heat-sink into place by pressing firmly on the top of each locating lug.

This will need a reasonable amount of force and will be accompanied by a loud snap as each locating lug snaps home.

Again, this will need a lot of force and you must ensure that the board is supported sufficiently when performing this operation.

Push two diagonally opposite lugs into place first and check that the heat-sink is level, then lock the two remaining lugs into place and again check that the heat-sink and fan assembly is secure and level. You have now performed what most people will consider to be the worst moment of putting together their own PC!

Once again, it pays to spend a little extra time checking and going over the procedure before actual fitment.

You can watch another short video here giving you further guidance on installing your heat-sink and fan assembly.





How to Install a CPU – CPU Fan Connections

On top of the heat-sink is a large fan which must be connected to the motherboard fan socket. Locate the fan connector and secure to the motherboard fan connector socket which should be located quite close to the processor.

Check your motherboard manual for details of this. Never run your processor without the fan connected - it will very quickly overheat and destroy itself.

Heatsink and Fan Fitted

After fitment of the fan connector to the motherboard connector header, tidy up the fan wiring so that it will not entangle itself in the fan or other components.

Nice and tidy and not pulled too taught is what we’re after here.

When your motherboard is fitted to your case and you boot up your PC, POST will list your CPU and you should enter the BIOS to confirm that the CPU settings are correct.

We hope you have found this article on how to install a CPU helpful and if you have any questions or tips be sure to let us know on our 'Readers Questions' page.

Return from How to Install a CPU to PC Tips and Tricks Homepage