What is Overclocking? The Absolute Beginner’s Guide to Understanding How Geeks Speed Up Their PCs
by Chris Hoffman on June 18th, 2013
Overclocking is the action of increasing a component’s clock rate, running it at a higher speed than it was designed to run. This is usually applies to the CPU or GPU, but other components can also be overclocked.
Increasing a component’s clock rate causes it to perform more operations per second, but it also produces additional heat. Overclocking can help squeeze more performance out of your components, but they’ll often need additional cooling and care.
What is Overclocking?
Your computer’s CPU comes from the factory set to run at a certain maximum speed. If you run your CPU at that speed with proper cooling, it should perform fine without giving you any problems.
However, you’re often not limited to that CPU speed. You can increase the CPU’s speed by setting a higher clock rate or multiplier in the computer’s BIOS, forcing it to perform more operations per second.
This can speed up your CPU — and therefore speed up your computer if your computer is limited by its CPU — but the CPU will produce additional heat. It may become physically damaged if you don’t provide additional cooling, or it may be unstable and cause your computer to blue-screen or restart.
Can You Overclock?
You may not be able to overclock your CPU. Many motherboards and Intel CPUs ship with locked multipliers, preventing you from tinkering with their values and overclocking your CPU. Intel sells expensive “Extreme Edition” CPUs with unlocked multipliers, targeted at enthusiasts that want to overclock and squeeze every bit of performance out of the CPU.
If you want to build the most powerful gaming PC imaginable with a water-cooling system so you can push its hardware to the limits with overclocking, you’ll need to take this into account when you buy the components and make sure you buy overclock-friendly hardware. If you have a standard CPU, you probably won’t be able to tinker with it much.
Why You Might Want to Overclock
The advantages to overclocking are clear: You get a faster CPU that can perform more operations per second. However, overclocking has become less critical over time — where overclocking once offered a more responsive desktop and faster performance in Microsoft Office, computers have become powerful enough that most users probably won’t even notice the difference. Your computer is likely bottle-necked by other things — perhaps a mechanical hard drive, if you don’t have solid-state storage — so you may not see a noticeable performance difference most of the time.
Gamers or enthusiasts that want their hardware to run as fast as possible may still want to overclock. However, even gamers will find that modern CPUs are so fast and games are so limited by graphics cards that overclocking doesn’t work the magic it used to.
How to Overclock
Every CPU is different, and every motherboard has different BIOS options. It’s not possible to provide a guide for overclocking that will work for everyone. But we’ll try to outline the basics, anyway:
- Ensure Your System Has Proper Cooling. Your CPU comes with a heat sink and fan from the factory, which are designed to handle the amount of heat produced at the CPU’s standard speed. Speed it up and it will produce more heat. This means
that you’ll probably need additional cooling. This can be in the form of an aftermarket heat sink that can dissipate more heat and/or a more powerful CPU fan that can blow the hot air away. You’ll want to have a good amount of free space inside your computer’s case so the air can move around and eventually be blown out by the fan in your computer’s case, which may also need to be upgraded. Air flow is very important for handling heat, as just having a heat sink or CPU fan won’t help if all that hot air stays trapped inside your case.
- Consider Water-Cooling: Hardcore overclockers may want to use a water-cooling system, which is more expensive. Water-based coolant is pumped through tubes inside of the case, where it absorbs the heat. It’s then pumped out, where the radiator expels the heat into the air outside of the case. Water-cooling is much more efficient than air-cooling.
- Overclock in the BIOS: You’ll need to go into your computer’s BIOS and increase the CPU clock rate and/or voltage. Increase it by a small amount, then boot your computer. See if the system is stable — run a demanding benchmark like Prime 95 to simulate heavy use and monitor your computer’s temperature to make sure the cooling is good enough. If it’s stable, try increasing it a little bit more and then run another test to ensure the PC is stable. Increase the amount you’re overclocking by bit by bit until it becomes unstable or the heat is too much, then drop back down to a stable level. Overclock little by little to ensure it’s stable, don’t just increase your CPU’s speed by a large amount at once.
When you overclock your CPU, you’re doing something you weren’t supposed to do with it — this will often void your warranty. Your CPU’s heat will increase as you overclock. Without proper cooling — or if you just overclock too much — the CPU chip may become too hot and may become permanently damaged.
This complete hardware failure isn’t as common, but it is common for overclocking to result in an unstable system. The CPU may return incorrect results or become unstable, resulting in system errors and restarts.
If you’re overclocking, you should slowly increase the clock rate and test every new level to make sure it’s stable. You should also monitor the temperature of your CPU and ensure that you have proper cooling. The cooling that came with your CPU probably won’t cut if. If you’re using a laptop without much space for additional air flow, don’t try to overclock — there’s generally just not enough space in a laptop to handle the heat.
If you are interested in overclocking, you’ll want to find information that applies to your specific hardware. The web is full of forums where people discuss their overclocking experiences, like Overclock.net , and guides for specific CPUs.
Note that even CPUs of the same model aren’t completely identical. One CPU may have more tolerance for overclocking, while another CPU over the same model may not be stable at the same speeds. This all comes down to natural variations in the manufacturing process.
Overclocking can apply to phones, too. There are apps that can overclock a rooted Android smartphone. However, between the additional heat and battery life hit, using these apps is generally not a smart idea.