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Installing the CPU
Prior to putting anything inside the case, it's a good idea to plug a few components into the motherboard. These parts are easier to install with the board outside the enclosure. First, put the motherboard on a flat, insulated surface. A typical tabletop will do so long as it's not made of bare metal.

To illustrate how the AMD and Intel sockets work, we have examples from each camp. Let's start with AMD's Socket FM1, which is designed for Llano-based APUs like the A8-3850 we pulled of the shelf. Click the video below to see the installation in motion.

Readying the FM1 socket requires little more than nudging the metal lever away from the socket and then swinging it all the way back. Next, find the small triangular marker in the corner of the socket. There's a corresponding mark in one corner of the CPU. Line up the two to ensure the CPU pins align correctly with the holes in the socket.

Those pins bend easily, by the way. Handle the CPU carefully, and be sure not to let any dust, lint, or stray pet hairs get caught up in the metal bristles. The CPU is best held by its edges, pinched between one's thumb and forefinger. Guide the CPU into the socket gingerly, ensuring the chip is fully seated, with no gap between the green rim of the CPU package and the surface of the socket. Then press down on the metal cap as you gently swing the lever back into its original position, tucked under the plastic tab on the side of the socket.

The Intel LGA1155 socket is similar to operate, but there are a couple of extra steps involved. First, you'll need to remove the protective plastic cover from the face of the socket. This piece shields the underlying pins, so be careful. There should be a tab on one edge that unclasps the cap from the socket. Don't toss this piece; motherboard makers sometimes require that it be put back in place if a board is returned for RMA service.

After removing the plastic cover, unhook the metal lever by pushing it away from the socket, and then swing back the lever. The LGA1155 arm swings back much farther than its counterpart on Socket FM1. Toward the end of its arc, the lever will lift the metal frame off the socket and back onto its hinge, exposing the pins completely. Don't freak out if they all look bent in the same direction; LGA pins are set at an angle.

Instead of relying on corner markers, Intel CPUs are aligned with LGA sockets using indentations in the processor package. Two semi-circular notches appear on opposing edges of the processor. A corresponding pair of nubs can be found on the inner walls of the socket. Match the notches to the nubs before slowly lowering the CPU into place. When the CPU is resting in the socket, wiggle the chip gently to make sure it's all the way in.

When handling LGA-style processors like the Core i7-3770K pictured above, hold the CPU by pinching the edges that don't have the notches. The socket's plastic frame makes room for your fingertips along these borders, allowing the CPU to be placed into the recessed socket with ease.

After the CPU is seated properly, flip the metal frame down onto the processor, and then slowly swing the lever back to its original position. Make sure the teeth at the end of the frame straddle the socket's anchor screw. If everything is lined up correctly, a little bit of force will be required to hook the lever under the metal tab that locks the socket shut.

Priming the processor
Now that the CPU is installed, it needs to be prepped for the cooler. Start by cleaning the heat spreader, the metal cap covering the top of the processor.

Unless you polished off a bag of Cheetos before installing the CPU, the heat spreader should look relatively clean. We're going to give it a quick scrub using a Q-tip dipped in rubbing alcohol. Brush the metal cap gently to remove any particulate or oily residue that might have been deposited on the surface. Feel free to use a higher-concentration isopropyl alcohol or a paper towel to get the job done. Be careful that your cleaning implement doesn't leave behind any fibers or debris of its own, though.

The stock coolers bundled with retail-boxed processors typically have a thermal interface material (TIM) pre-applied to the base of the heatsink. If you don't have a separate tube of thermal paste, leave the factory coating as-is. You can skip straight to installing the cooler. Folks who want to replace the stock thermal interface with another compound will first need to get rid of the original.

Why bother? Because the compound applications found on stock heatsinks are typically thicker than is optimal for efficient heat transfer. Thermal compounds are used to fill tiny scratches and other surface imperfections, ensuring an unbroken physical interface between the CPU and cooler. Only a thin layer is required, one enthusiasts typically prefer to spread themselves.

The TIMs found on stock heatsinks are fairly hearty, so some scraping is required to remove them. Avoid using metal tools, which can leave scratches in the base of the heatsink—the very thing we're trying to counteract. Find something with a hard plastic edge, like a credit card or the scraping tool in the video embedded above. Once the TIM has been scraped off, scrub the surface with rubbing alcohol. If any residue remains, you may need to resort to a more noxious solvent. Nail polish remover does a pretty good job of cleaning up persistent thermal paste.

If your cooler is TIM-free, it's still worth taking a moment to clean the base of the heatsink. You never know what the surface has picked up on its journey from an overseas factory. Another alcohol-soaked Q-tip should do the trick.

There are different schools of thought on how best to apply thermal compound. Heatsink makers typically recommend squeezing a pea-sized dollop of the goop onto the center of the CPU's heat spreader. These days, most suggest plopping the heatsink right down on top of that lump. Tightening the cooler's retention mechanism will flatten the blob of compound, spreading it evenly between the CPU and heatsink.

If you're really anal, you can spread the compound by hand using a credit card, a razor blade, or something like the plastic tool in the video above. The compound can even be spread with a finger, but you'll want to wrap the digit in a plastic bag first. Some compounds, usually the silver stuff, can stain skin and clothing.

We like to keep a paper towel handy to clean the scraper after the last few swipes across the processor. This obsessive-compulsive step sheds some of the excess compound. Don't hesitate to take the lazy route and rely on the heatsink to spread the goo, though. We do it all the time, and in our experience, the approach doesn't result in substantially higher CPU temperatures.

Before moving on to installing the heatsink, make sure no thermal paste has made its way onto the motherboard, where some flavors of the material have the potential to short exposed connections. Typically, white compounds like the one we're using aren't conductive; it's the silver stuff you have to worry about. Unless you've really made a mess, an alcohol-soaked Q-tip should be able to mop up any accidents with surgical precision. There's no need to buff out smudges on the metal retention bracket, which is already conductive. Just make sure the circuit board and any adjacent electrical components are clean.