How to Install a CPU and Heatsink

Mark Kyrnin is a former Lifewire writer and computer networking and internet expert who also specializes in computer hardware.

Updated on February 10, 2021

What to Know

Open the processor socket on the motherboard. Align the processor and the socket. Lower the CPU until the pins are in the holes.
Lock the CPU in place. Apply a thermal pad or thermal paste to the exposed portion of the processor.
Align the heatsink above the processor and clamp it in place. Plug the power connector for the cooling unit into the fan header on the board.

This article explains how to install a heatsink on a CPU with the pin-grid array processor design used by most manufacturers.

How to Install a CPU and Heatsink

If you're building your own PC, you need to know how to install a CPU onto the motherboard. You must also attach a heatsink fan on top of the processor to keep it cool.

Motherboards only support specific brands and types of processors, so read all the documentation for your motherboard and processor before proceeding. In addition, refer to the documentation for the motherboard, processor, and cooling unit. You need to know the locations of the processor slot, heatsink mounting clips, and the CPU fan header.

These instructions assume that you are installing the CPU onto the motherboard before installing the motherboard into the computer case:

The steps for replacing an existing processor are the same, but you must first remove the original CPU by reversing the installation instructions.

A hand opening the CPU socket on a motherboard

Locate the processor socket on the motherboard and open the processor slot by lifting the lever on the side to the open position.

A hand aligning the CPU to the socket on a motherboard

Locate the keyed portion of the processor that is signified by a diagonal corner of the pin layout. Align the processor so that this corner matches up between the processor and the socket.

Insert the CPU

With the processor aligned based on the key, make sure the pins are lined up with the socket and gently lower the CPU so that all the pins are in the proper holes.

If the processor or cooling solution came with a protection plate, align it over the processor as instructed with the product documentation.

A hand locking a processor in place on a motherboard

It is best to spread the paste evenly by covering your finger with a clean plastic bag. This prevents the paste from being contaminated.

Thermal compound being applied to a motherboard

A hand aligns the heatsink over a CPU

Align the heatsink or cooling solution above the processor so that the clamps are in line with the mounting points around the processor.

Be careful at this stage as a lot of pressure will be placed on the board. A slip of a screwdriver can cause a lot of damage to the motherboard.

A hand attaching a heatsink to a motherboard with a screw driver

A hand attaching a heatsink fan header to a motherboard

Locate the power lead for the cooling solution's fan and the CPU fan header on the motherboard. Plug the power connector for the cooling unit into the fan header on the board. It should be keyed, but make sure it is secure.

When all the remaining parts necessary for operation are installed, the motherboard BIOS must either detect or be told what type of processor is installed on the board. Refer to the documentation that came with the computer or motherboard on how to configure the BIOS for the proper CPU model.