How to overclock your CPU: fine-tuning for your processor

The CPU (Central Pro­cessing Unit) is the part of a computer that processes data and com­mu­nic­ates commands. For this reason, the CPU plays a crucial role when it comes to how quickly and reliably a PC operates. In addition to the computer’s current usage, it is the CPU’s per­form­ance capacity that has the biggest impact on the speed with which the re­spect­ive pro­gram­s­pro­grammes and processes are able to run.

The most important unit for measuring a processor’s per­form­ance capacity is clock speed. This is specified in hertz (Hz) and provides in­form­a­tion on the speed with which data and commands are being processed. The higher the clock speed, the quicker the computer can complete tasks. Pro­gram­s­Pro­grammes that demand a lot of pro­cessing power also perform better with higher clock speed.

If the CPU is somewhat outdated, it may be the case that the clock speed de­term­ined by the man­u­fac­turer for newly-developed high-per­form­ance pro­gram­s­pro­grammes is no longer adequate. This will become no­tice­able in the form of long delays as well as an ex­cep­tion­ally high CPU usage, which can cause pro­gram­s­pro­grammes to tem­por­ar­ily freeze, and in the worst-case scenario can even lead to a system crash. However, there is an option to increase per­form­ance capacity and ac­cel­er­ate data pro­cessing: over­clock­ing the CPU.

In addition to the data transfer rate, the clock speed is one of the most crucial units for measuring how fast a CPU completes the computing process needed to process data. This clock speed is usually de­term­ined by the man­u­fac­turer and indicated in the CPU’s product spe­cific­a­tion. However, in most cases, the value does not represent the processor’s maximum per­form­ance capacity. Rather, the indicated speed meets the demands of most users, while at the same time enabling optimal energy-ef­fi­ciency and the best lifespan for the CPU.

But what happens if the CPU’s clock speed is in­ad­equate for your computing needs? This can happen, for example, if you use high-per­form­ance pro­gram­s­pro­grammes and raw data formats for editing photos and videos, or if you are a pas­sion­ate gamer. Instead of con­sid­er­ing a re­place­ment of your CPU, you can manually increase the CPU’s clock speed in order to improve pro­cessing power. This is called over­clock­ing the processor. The over­clock­ing des­ig­na­tion came about because the clock speed that was ori­gin­ally indicated is de­lib­er­ately exceeded.

It’s also worth men­tion­ing that over­lock­ing is not only possible with the CPU, but with all PC com­pon­ents that operate with a peri­od­ic­al clock signal. That is to say, for example, a video card or RAM. If you operate all hardware com­pon­ents in-sync with a higher clock speed, you can increase your PC’s system per­form­ance con­sid­er­ably.

Before you get down to action, you should be aware that your PC operates as a complete unit. If you change specific para­met­ers, this also has an effect on other com­pon­ents. The most important thing is to provide suf­fi­cient cooling because when you overclock your PC, it will in­ev­it­ably produce more heat. To protect from over­heat­ing, the system auto­mat­ic­ally curbs its per­form­ance (in other words, the clock speed) as soon as the sensors report tem­per­at­ures above the es­tab­lished threshold. This is exactly what you don’t want to happen when you overclock the CPU. Moderate over­clock­ing (up to two speed grades higher than spe­cific­a­tions) should be safe, but if you plan on doing heavier over­clock­ing, you should set up a good cooling system. You can do this by either in­creas­ing the speed of the built-in cooler or by ret­ro­fit­ting a high-per­form­ance external cooling system (e.g. coolers using water or nitrogen).

Another safety hazard is increased voltage. Make sure that the power supply can withstand this value or limit in­creas­ing the voltage to the extent that it is permitted in the technical spe­cific­a­tions. In general, we recommend that the per­form­ance increase should only exceed the clock speed increase. Although it’s true that raising the voltage does produce much higher per­form­ance, it demands so much from the in­di­vidu­al com­pon­ents that the life span in most cases decreases con­sid­er­ably.

If the technical spe­cific­a­tions of your hardware and software meet the re­quire­ments for a higher clock rate, then you can get started by in­stalling the necessary mon­it­or­ing and testing tools, and under careful ob­ser­va­tion, in­cre­ment­ally change specific para­met­ers for your CPU.

First, you should install tools with which you can monitor the CPU tem­per­at­ure and use. They allow you to check what effects the clock speed increase had and also whether the system remains stable under added stress. We recommend CPU-Z and HwiNFO, which are both available as freeware. With these tools, you can not only monitor the clock speed, tem­per­at­ure, and voltage in real-time, but also view graphs of the activity and per­form­ance data curves.

You’ll find the settings and options for over­clock­ing your processor in your computer’s BIOS (Basic Input/Output System) or in the UEFI (Unified Ex­tens­ible Firmware Interface) in newer PCs. In most cases, you can access these when turning on your computer by pressing the “delete” key or one of the function keys. With regard to main­boards, most of them include tools via which you can perform the setting changes for over­clock­ing. However, the BIOS/UEFI is more suitable for making ad­just­ments, as you can bypass possible mother­board man­u­fac­turer re­stric­tions from there.

For over­clock­ing the processor, the front-side bus, mul­ti­pli­er, and core voltage values are important. You may need to change into your BIOS/UEFi’s expert mode be­fore­hand in order to be able to see and change these values.

Record the standard settings as well as the values for every specific over­clock­ing step so that you can undo the changes at any time if the system becomes unstable. The CPU’s clock speed consists of the front-side bus and a mul­ti­pli­er. Make sure you record the defaults for these values.

Most pro­cess­ers have a standard activated turbo or booster function that auto­mat­ic­ally increases the clock speed when there’s higher usage. You should de­ac­tiv­ate this before changing settings so that you don’t distort the results during later test runs.

In­creas­ing the mul­ti­pli­er promises the most effective per­form­ance increase. You should proceed with this in the smallest possible steps (either 0.5 or 1), then restart the PC and check the clock speed as well as the tem­per­at­ure and voltage values. If your system doesn’t indicate any issues during the sub­sequent stress test, you can increase the mul­ti­pli­er value again.

With many man­u­fac­tur­ers, the mul­ti­pli­er cannot be changed, or can only have minimal changes made to it. In this case, you must fine-tune the front-side bus in order to overclock the CPU. Here, small steps and con­tinu­ous mon­it­or­ing are the surest way to protect the system from over­load­ing.

In most modern mother­boards, the CPU’s clock speed and voltage are coupled to each other. This means, that as soon as you make changes to the mul­ti­pli­er, the voltage auto­mat­ic­ally increases to the optimal value. If you still want to manually increase the value, you should proceed with extreme caution. A high-per­form­ance cooling system and careful mon­it­or­ing of the tem­per­at­ure are essential to prevent ir­re­par­able damage to your PC.

After every change of a specific parameter, your PC must be checked to see if it still runs stably. It’s not enough to just restart the system and open a few pro­gram­s­pro­grammes and websites. Because you are over­clock­ing your CPU in order to improve pro­cessing power, you must also stress test the stability of the PC with the new settings under a heavy load. Otherwise, you could find yourself in a situation where everything looks good at first glance, but your system will not withstand the constant strain caused by games or video editing.

In order to simulate the maximum load, there are so-called stress tests which push the CPU (and other com­pon­ents) to the limit. You should carefully monitor the CPU tem­per­at­ure and clock speed while the pro­grampro­gramme runs, and im­me­di­ately stop the test if the values rise to a critical limit. At this point, adjust the changed para­met­ers downwards again until you have op­tim­ized­op­tim­ised your system so that it runs stably with a heavy load on a sus­tain­able basis.