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Learning how to install a CPU is the first skill every PC builder needs — and it is easier than it looks, as long as you handle the chip carefully, line up the markers and never force anything. A CPU is the most expensive part in most builds, so it is worth taking the time to do it right.
Before you start: what you need
You need the CPU, the motherboard, the cooler and the thermal paste — and a clean, flat surface to work on. Check that the CPU and the motherboard match before you start: an AM5 chip needs an AM5 board, and an LGA1700 chip needs an LGA1700 board. Our how to check CPU compatibility guide shows you how to verify the parts, and our best CPU and motherboard combos guide lists pairs that are known to work. Our how to build a PC guide covers the whole build, step by step.
Step 1: prepare the motherboard
Take the motherboard out of its box and put it on the box itself — the box is a good, safe work surface. Open the CPU socket: on an Intel board, lift the metal lever and open the cover; on an AMD board, lift the lever to open the socket. Do not touch the pins in the socket — they are fragile, and a bent pin can kill the board. If you are building with a Ryzen 5 9600X or a Core i5-12400F, the process is the same — only the socket looks different.
Step 2: install the CPU
Hold the CPU by its edges — never touch the pins or the gold contacts underneath. Line up the small triangle on the corner of the chip with the triangle on the socket, and lower the chip straight down. It should drop into place with no force at all. If it does not sit flat, lift it out and check the alignment — do not push it. Once it is flat, close the socket and lock the lever. The chip is now installed, and it should not move.
Step 3: apply the thermal paste
Thermal paste fills the tiny gaps between the CPU and the cooler, and without it the chip will overheat. Our how to apply thermal paste correctly guide shows the pea-sized dot method: one small dot in the middle of the chip, and the cooler spreads it when you mount it. Do not use too much — a big blob will squeeze out the sides and make a mess — and do not spread it with your finger.
Step 4: install the cooler
Mount the cooler on top of the CPU, following the cooler’s instructions, and tighten the screws in a cross pattern — a little at a time on each side, so the pressure is even. Connect the cooler’s fan cable to the CPU fan header on the motherboard, which is usually labelled CPU_FAN. Our CPU cooling basics guide and our how to choose the right CPU cooler guide cover the cooler choice.
Step 5: boot and test
Once the cooler is on, finish the build and power it on. If the PC boots into the BIOS, the CPU is installed correctly. Check the temperature with our how to monitor CPU temperature guide, and run a benchmark with our how to benchmark your CPU guide to confirm it is stable. If the PC does not boot, check the power cables and the RAM first — the CPU is rarely the problem.
The bottom line
How to install a CPU, in short: line up the triangle, drop it in gently, add a dot of paste, mount the cooler and boot it up. Take your time, do not force anything, and you will have a working PC. See our why is my CPU overheating guide if the temperature is high after the install, and browse our troubleshooting tips for more fixes.
