How to Install a CPU and Heatsink

The most critical part of building your own computer is knowing how to install a CPU and how to install a heatsink. The CPU is the brain of your computer and is the most delicate part. It’s easy to damage, although most CPUs are designed so that they’re nearly impossible to install incorrectly.

Installing a CPU is one of the most important steps in building a PC

The heatsink cools the CPU and keeps it from frying. Heatsinks are fastened to the top of the CPU and sometimes come with an additional substance called “thermal paste.” This is a thin gel that adds an additional layer of cooling. Let’s look at the basic steps for installing the CPU and heatsink.

1. Locate the Processor Socket

Before you can install a CPU you should find the processor socket on the motherboard. This is the square socket with numerous pinholes in it. Lift the lever to the side of this socket so that you can install a CPU into it.

Look closely at the pin pattern on your CPU socket. Notice that there is a diagonal corner where it appears some pinholes are missing. It might appear as a triangular pattern. This is there to help you properly align the CPU to the CPU socket. Carefully grab the CPU by the sides and turn it over to examine the pins at the bottom.

Compare the alignment of your pins with the pattern on your socket and you’ll see that there is only one correct pattern for alignment. Again, it’s virtually impossible to install the CPU incorrectly unless you force it. Make sure that you have the CPU and socket aligned correctly before proceeding onto the next step.

2. Mount the CPU

Once you are sure that the CPU pins and socket pins holes are matched up correctly, you can insert the CPU into the socket. Again, be sure to use that diagonal pin pattern as your guide.

You might meet some resistance as you are pressing down. This is a delicate procedure – and if you’ve never before learned how to install a CPU, you might think you are doing it incorrectly. However, learning how to install computer components takes practice. The resistance is normal. Again, the socket design and CPU pin patterns are designed to match perfectly.

Press down past the resistance point and then the CPU will slide smoothly into the socket. The CPU may make a snapping sound as it slips into the socket. When you’re sure it’s complete, lower the lever at the side of the socket to lock the CPU into the socket.

Check to see if your particular brand of CPU or cooling solution came with a protection plate. If it did, place it above the CPU as explained in your documentation.

3. Apply the Thermal Compound

Next comes the thermal compound. Some people choose to avoid this step altogether, while others who teach on how to install a heatsink swear by it.

Generally a properly designed heatsink will ensure that you may not need a thermal compound. However it doesn’t hurt to be too safe, especially with CPU processor speeds increasing and generating more and more heat. Thermal paste can usually shave off a few extra degrees of hot temperature off of your CPU.

Apply the thermal paste to the areas of the CPU that will make contact with the CPU. Begin by applying a little bit of the gel to the center of the CPU and then gently spreading outward. Don’t apply too much of thermal compound. A little dab will do you. Be sure to spread an even, thin layer of the gel to ensure that there is complete coverage over your CPU.

4. Install the Heatsink

Now we learn how to install a heatsink. This is a very crucial step. If the heatsink is not installed properly it might come loose. Your CPU will overheat and be toast in no time.

Before we explain how to install a heatsink, check to see if your heatsink has a fan separate from the unit. If it does, you’ll need to attach the fan to the heatsink first before attaching the heatsink to the CPU.

When you’re ready, mount the heatsink over your CPU according to the specifications for your manufacturer. The directions will vary. Some heatsinks are installed by requiring you to clamp down on them with levers and attaching them to metal hooks on the motherboard. With other heatsinks you may have to screw the whole unit into the motherboard.

Whatever the procedure, follow it closely and be very careful. If you need to use a screwdriver to install the heatsink you could very easily slip and damage your system components.

5. Install the Heatsink Fan Header and Configure BIOS

The final step in learning how to install a heatsink involves connecting the power leads from the heatsink to their proper headers on the motherboard.

Locate the header for the CPU fan on the motherboard. Then plug the power cable from the heatsink into the fan header on the motherboard. There will be more than one header on the motherboard, so be sure that you pick the right one. Choose the wrong one and your computer might get a power surge that will fry the processor.

Check the documentation that came with your motherboard to properly locate the correct header. Once installed, be sure that it is securely in place.

Afterwards, assuming that the rest of your computer has been installed properly, you can configure the BIOS. The BIOS will need to detect the type and speed of the computer processor that has been installed. Again, the exact procedure will vary depending on the manufacturer; check the documentation that came with your motherboard.


Learning how to install computer components like a CPU and heatsink might seem like a daunting task to someone who’s never done it. However, it’s not as hard as you think. CPUs and heatsinks being made today were designed to fitly snug together with a minimum of fuss.

You don’t need much in the way of mechanical skill and about the only tool you will need is a screwdriver. Yet this is by far the most delicate operation you will perform on your computer. Once you pass this hurdle, everything else will be a breeze.