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 programs 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. Programs 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If the CPU is somewhat outdated, it may be the case that the clock speed de­ter­mined by the man­u­fac­tur­er for newly-developed high-per­for­mance programs is no longer adequate.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 programs 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 programs 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 programs 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 program 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 optimized your system so that it runs stably with a heavy load on a sus­tain­able basis.