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Avast Academy Performance Gaming How to Safely Overclock Your CPU on Windows

How to Safely Overclock Your CPU on Windows

Want to improve your computer’s performance? Overclocking your CPU is a great way to make your PC run faster — without spending a cent on an expensive upgrade. It’s achieved by running your CPU at a higher-than-intended frequency. Read on to learn how to push the processor to its limit, check the computer’s temperature, and achieve a stable overclock.


Can I overclock my CPU?

Let’s start with the most critical question: Can you overclock your CPU? Not every processor supports overclocking. When it does, the CPU has what’s called a “unlocked multiplier.” 

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    One way to find out is to examine the name of the CPU. Intel adds the letter “K” to processors that can be overclocked, such as the Intel Core i7 9700K. Also, all processors from the Intel “X” series (used primarily for professional multimedia) can be overclocked. 

    On the AMD side, there’s nothing to worry about. All modern AMD Ryzen CPUs are “unlocked” and can be overclocked. If you have an older model, it’s worth an online search to see if overclocking can be achieved. 

    In theory, any CPU can be overclocked. However, that can be done only by raising what’s called the base clock, that is, the clock speed of your motherboard and your entire system (including the CPU, RAM, and PCI Express devices,such as sound cards or graphic cards). However, just because you can overclock a CPU doesn’t mean you should. If you push the technology too far, expect to encounter CPU stability issues. 

    The following sections explain how to benchmark your system to check the baseline performance of your CPU, stress test it, check the temperature, and — finally — overclock it!

    Determine your CPU's core temperature

    Before you get started, it’s critical to check your CPU’s temperature, as overclocking will increase it — and you’ll want to measure the change.

    Perform a system stress test

    If you aim to perform a serious CPU overclock, you should look at stress testing the CPU for a few hours. You want to be confident that the current system is stable under the current default clock speed. If you encounter problems later, you want to know why!

    My favorite tool for this use is Prime95. Again, check your temperatures as you’re going through this process (see the step above).Stress testing your CPUThis puts a constant 100% load on all CPU cores. Let it run for one or two hours and see what happens.

    Check your CPU’s performance

    Before you can recognize improvement, you need to know where you’re starting! You should begin by getting an understanding of your current CPU’s performance. One good tool for that task is Cinebench, which simulates a rendering workload. Extract the archive and fire up Cinebench Windows 64 Bit.

    Once Cinebench is launched, click on the Run button next to CPU. When the rendering is complete, it shows you the current score. Write down that number for later comparison.Getting baseline Cinebench results for later comparisonAnother benchmark tool I like is 3DMark Basic, which is focused on gaming performance.
    As you benchmark, you should monitor your CPU’s temperature as mentioned above. Learn how hot it gets under this load.

    Access your BIOS

    Ready to get started? The only reliable way to overclock your system is to change the settings in the computer’s BIOS. The BIOS (sometimes referred to as UEFI) contains the PC’s key settings.

    To access the BIOS, you must turn off your computer and turn it back on. As the computer restarts, press the DELETE, F2 or F10 key repeatedly. Doing so enters your PC’s BIOS controls. The exact key combination varies by manufacturer brand and model. Usually, a message is displayed, something along the lines of, “Press F2 to enter Setup.”

    PC’s BIOS controlsYour BIOS likely looks different from the ones in these screenshots, but you should find text something like, Advanced CPU Core Settings or OC/Overclocking." This is where to find the settings to overclock the CPU.Using CPU multipliers to increase the clock speedChoose between automatic and manual overclocking

    Depending on the motherboard manufacturer, the BIOS may provide an Automatic Overclocking or OC Level function. These give you a bit of an overclocking boost at safe levels, but the results usually are nothing special. That’s why we recommend going with the manual approach outlined in the next step.

    Adjust the CPU multiplier

    The first step to increase the clock speed should be to increase the multiplier. This uses the base clock built into the motherboard (usually 100 MHz); multiplying that number yields your clock speed. For example, a multiplier of 36 (x100 MHz) gets you 3.6 GHz.

    Gradually raise the multiplier one step at a time. This is usually done by typing in the number or using the “+” key on the keyboard. Add it slowly. Treat this as an iterative process. Speed up the computer a little bit; then, if all goes well, go back and speed it up some more. You can start by increasing the multiplier for one core and go slowly for the others. The more cores you overclock, the hotter (and more unstable) things become. 

    Save your settings and reboot the system. Stress test and benchmark to estimate the CPU stability and performance.

    However, overclocking the multiplier only gets you so far (in our case from 36 to 39) without things becoming unstable. That’s because your CPU requires a bit more “juice” to get going.Increasing the voltage under your UEFI / BIOS to support a stable overclock.To give it a bit more, find the CPU voltage setting. In your BIOS controls, this may be called CPU VCCIN, CPU Vcore, Dynamic Vcore, or simply CPU Voltage. By default, it usually is set to 1.25 or Auto. Increase this value slowly, for example to 1.4 or 1.5. This gives you a bit more room for overclocking, so you can try increasing the multipliers a bit more.

    However, every time you overclock a CPU, the computer runs hotter. So make sure you have proper cooling!

    By increasing voltage and multipliers one by one, you’ll eventually find the maximum overclock on your system. 

    In this example, I gradually increased the clock speed from  3.6 GHz on a Core i7 5820k to 4.6 GHz by using a multiplier of 46 and a voltage of 2.1. Doing so improved the Cinebench score from 998 to an insane 1,317.Cinebench results before overclockingCinebenchThat’s a performance improvement of 30%. Others pay hundreds of dollars to achieve a similar speed increase!

    What happens if I get a black screen when I overclock?

    In some cases. your PC won’t boot up after an overclock. Don’t worry. Resetting the BIOS settings reverts all settings to the default values, so you can try the last setting that worked for you. Usually the motherboard has a button that says “Clear CMOS” or “Reset CMOS.”

    In the worst case, you can pull out the little battery on your motherboard, wait 10 seconds, and put it back in. Refer to your manual for more instructions.

    What does overclocking do, exactly?

    Overclocking allows you to run your processor at higher clock speeds than originally intended. This lets you do things such as edit videos or photos faster, game smoother, and generally make things feel a tad snappier.

    In the example above, we went from 3.6 GHz to 4.6 GHz - quite an achievement! So that’s what overclocking does. Besides your CPU, you can also overclock your GPU.

    Why should I overclock my CPU?

    If you want more performance, be it for gaming, rendering, coding, or simply your day-to-day tasks, you can try to achieve a higher core clock. That saves a lot of money, compared to the cost of upgrading to a new CPU or even a new computer.

    Should I overclock my CPU for gaming?

    Absolutely! While many games are “GPU bound,” meaning that most calculations happen on the graphics card, a significant part of gaming performance is also dependant on processor performance. An overclock can give you more frames per second in many scenarios. However, overclocking doesn’t help much if your OS and its programs aren’t properly optimized. To make sure no software or setting is slowing you down, check out our guide on how to speed up PCs.

    Is overclocking safe?

    Yes — within limitations. However, there are some myths about the process.

    It’s almost impossible to “fry” your CPU by overclocking it. If the clock is set too high, your PC will simply reboot or bluescreen. As we mentioned above, it’s easy to revert to the original settings using the CMOS reset.

    However, giving the CPU more voltage and higher clock speeds puts additional stress on it. Realistically, it means that you reduce the CPU’s lifespan a bit. In reality, you might be reducing the CPU life from 15-20 years to maybe 12-15 years, but it’s hard to say. It’s almost certain you would replace the computer before then anyway. 

    We recommend overclocking on gaming PCs you’ve built yourself with proper cooling in mind. For more on that, including our recommendations, check out our article on how to build your own gaming PC. 

    If you don’t want to risk it or need an additional boost, you can also go the software route of tuning your PC to the maximum. At Avast, we developed a patented technology called Sleep Mode, which detects and disables resource-draining programs when you don’t actively use them. It’s best to put everything to sleep to get the maximum FPS out of your system. Click the button below to download a free trial of Avast Cleanup, then go into the Speed Up section and look for Background and Startup Programs.


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