How to Upgrade a CPU

Here's how to perform a central processor upgrade

Learning how to upgrade a CPU is a right of passage for any DIY PC enthusiast. It's not overly complex, but it is something that needs to be executed carefully, as there is real potential to damage your CPU and your motherboard, and even if you do it mostly right, leave components with inadequate cooling which can lead to overheating and further damage.

That's why it's important to learn how to upgrade a processor properly, with clear, step by step instructions.

Before You Buy

The first step in any CPU upgrade journey is buying the right one. If you're starting from scratch with a brand new PC and are looking to upgrade the entire system in one go, then a great place to start is with our AMD vs Intel guide. Picking one camp over the other will lead you down the path of bespoke motherboards and exclusive features, even if both camps offer excellent processors for a variety of budgets, whether you're replacing a CPU for gaming, work, or a little of both.

When you've decided on the brand you're targeting, take a look at a list of the best CPUs money can buy to help you pick the right CPU for you. Make sure to pick a CPU that is compatible with your motherboard. Don't spend too much, either, as there are diminishing returns after a certain point, unless you're building the most high-end of gaming PCs, or the most powerful of video transcoding machines. Even then, the top chips can be inordinately expensive. A focus on more meaningful components (like the graphics card for gaming) can be of more importance, depending on what you want to do with your PC.

What You'll Need For a CPU Upgrade

Along with the CPU itself, there are also a few tools and items you'll need to complete a successful CPU upgrade.

  1. An anti-static wrist strap: This helps to ground you while you're performing the upgrade and ensures that no static electricity damages your new processor or any of your other PC components.

    Anti-static wrist strap
    StarTech/Amazon
  2. A CPU cooler: This may be included with your existing CPU or the new one you buy. Not all processors come with one, so make sure to buy a cpu cooler that will work with your cooling and noise level demands. Also make sure it fits your CPU socket of choice, although most modern coolers will fit most modern CPUs from both AMD and Intel.

  3. A good quality heatpaste (also called thermal paste): Coolers and the integrated heatspreader (IHS) used on modern processors are relatively flat and smooth, but on the microscopic level, there are plenty of grooves and rivulets that make for an imperfect surface for heat transfer. That's where a high quality heatpaste can come in. It fills the gaps and ensures that the maximum amount of heat is transmitted away from your processor and into the cooler.

  4. Lint-free cloth and 99% isopropyl alcohol: This removes old heatpaste and is necessary if you plan to re-use your existing cooler.

  5. A Phillips screwdriver: Most coolers require some screws to hold the the heatsink and sometimes its fan(s) in place. Most often they use Phillips head screws. A long screwdriver can make the job of installing a cooler much easier.

You also want to prepare your CPU upgrade surface effectively, making sure it's clear of dust, dirt, and debris. Make sure it's not a conductive surface like metal, nor a carpeted floor. A wooden or ceramic desk surface is ideal. If you are standing on a carpeted surface, it's recommendable to wear rubber soled shoes as a secondary protection against static discharge.

Doing so in a well lit area, or supplementing overhead lights with a desk or headlamp can also make the process much easier.

How to Replace a CPU

Before you get started with the process of replacing your CPU, backup any important data on your PC. Nothing is likely to happen to it, but there is always a risk of needing to format your hard drive when changing PC components and this step guarantees you won't lose anything valuable if you do.

When that's done, remove all the cables from your PC and take off its side panel, attach your anti-static wrist band, and make sure you have all your tools and components to hand.

The following images show the motherboard removed from the PC to make for clearer photography. This is a step you can take to improve ease of access to components, but it's not necessary in most cases.

  1. Remove the original CPU cooler. If it's the stock Intel/AMD CPU cooler, this will involve unscrewing the four corner screws. For other coolers, you may need to refer to the manufacturer's manual. If you plan to reuse the cooler, remove the old heatpaste using a lint-free cloth and 99% isopropyl alcohol.

    Remove CPU cooler
    Javier Guerrero/GettyImages
  2. Lift the retention arm that holds the CPU in place. This should require light pressure, but will come up easily.

    Removing old CPU
     Javier Guerrero/Getty Images
  3. Carefully remove the old CPU, holding it by the edges and avoiding touching the pins/contacts on the underside. Place it somewhere supportive and non-conductive.

  4. Take the new CPU and look for a small, golden triangle in the corner of its top side. Line that up with the similar arrow on the CPU socket and install the CPU, making sure not to touch the underside pins or contacts. Gently nudge it back and forth once in to ensure that it is safely deposited correctly into the socket.

    Install CPU
    Javier Guerrero/Getty Images
  5. Press down on the retaining arm to lock the CPU in place.

  6. If your CPU cooler does not have pre-applied heatpaste, use your own to add a pea-sized amount to the center of the CPU.

    It might not look like much, but when the cooler is attached it will spread out, looking something like this:

    Heatpaste spread
    Richard Lewis/Flickr
  7. Using the mounting instructions for your new or existing CPU cooler, place it gently on top of your CPU. If it uses multiple screws to fix it in place, screw them in partially beginning with screws on the opposite side of one another. For a four-screw cooler, you could start in one corner, then do the one diagonally opposite before screwing in the others. Screw them in a few turns at a time until all are hard to turn. It should not require extreme force. Be wary of overtightening.

    Installing cooler
    Javier Guerrero/Getty Images
  8. Find the 3 or 4 pin fan header on your motherboard, often designated CPU_FAN and attach the fan cable to it.

    Fan header
    Javier Guerrero/Getty Images

Before replacing the side-panel of your PC, it is recommended that you plug in only the bare necessary cables—power, monitor, keyboard, and mouse—and attempt to power it on. If it boots up, congratulations, you have successfully replaced your CPU and can shut it down, close the case and tidy everything away.

If not, you should retrace your steps to make sure you completed everything successfully.