Overclocking: A Beginner’s Guide

For those who are unaware, as the name might suggest, overclocking involves increasing the clock speed (running speed) of your processor to make it operate faster. This has the effect of increasing the power of your computer, sometimes quite considerably, and for free. All you need is some time to digest the ideas and some more time to put them into practice.

This guide aims to introduce you to the basic ideas and knowledge that are needed to start overclocking your processor.

Why Would You Want to Overclock Your PC?

Generally people either want to get more power out of an old system, or they do it to see how fast they can get a newer system to run to make their machine more powerful.

Personally, I started looking into overclocking a few years ago when I couldn’t afford a new computer and my processor was the limiting factor. It was back in the days when the Core2Duo Dual Core processors had been superseded by the quad cores and I needed more power!

I had an E4500 processor that was running at 2.2GHz out of the box and I managed to up it to a stable running speed of just under 3GHz (2.926GHz). That’s a 33% increase on the stock running speed for nothing more than some of my time and fair bit of reading.

Obligatory Warning

This can harm your computer. Not in a “Oh, I lost a file” kind of way, but in a “Oh, I fried my processor, motherboard and RAM” kind of way! This is obviously the worst case scenario, and without wishing to tempt fate, I’ve never damaged any of my components by overclocking them. Consider yourself warned, and it goes without saying that neither I, nor Envato, take any responsibility for any ill effects or damage caused by any action taken as a result of reading this article.

Further to this, some systems are not set up to be overclocked. Generally proprietary systems such as those by Dell, HP and other manufactures will have the necessary parts of the BIOS locked so that you cannot manually override it. This is for safety, stability of the system and so that they don’t get calls to customer services blaming the company when the user fried their processor!

What You Need to Know

There are some terms that are synonymous with processors and related hardware that you should be aware of to follow this guide.

  • Base Clock/ Front Side Bus (FSB). This is the main setting that is usually changed to increase CPU speed. The base clock will be written in MHz, eg 166MHz.
  • The CPU multiplier is another setting that is core to the calculation of CPU speed. The base clock is multiplied by the multiplier (as the name would suggest!) to reach the overall speed of the processor. For example, take a base clock of 166MHz and multiply it by the multiplier of 18 and you get the CPU speed, in this case 3GHz (it is more precisely 2.988GHz, but is usually rounded) It should also be noted that the multiplier is usually locked, that is to say you cannot increase it. More expensive CPUs in the Intel range sometimes have unlocked multipliers that allow you to increase as well as decrease it, these are the Extreme Edition and Engineering Sample CPUs.
  • RAM divider. This is the same deal as the CPU multiplier, but for the RAM, so you take the base clock of 166 and multiply it by 10 and you get 1666 Ram speed, for example.
  • Ram timings, or latency. Ram has different parts of its performance rated with separate timings, lower numbers are better, and higher numbers are worse. It is usually a set of four numbers separated by commas. Explaining this further is not necessary at this point, but be aware that it may be necessary to loosen the timings (make them larger) if the speed of the ram is increased.
  • Voltages. Each of the components in your system has separate voltage that can be altered, the most commonly altered are vcore (CPU voltage), vdimm (RAM voltage), and vMCH (Northbridge/memory controller) As the speed increases as you overlclock the cpu, the amount of voltage that it requires will increase. This is usually done manually. Some BIOS manufacturers have included a way to set the voltages to increase automatically. Whether to do this or not is your own choice. Sometimes it works, sometimes only manual configuration will do.

What You Need to Have

Suggested Hardware

The hardware, for the most part is whatever you have already. the only thing to bear in mind is that overclocking stresses the system more than usual, so some parts will need to be up to scratch. if you have a cheap Power Supply (PSU) you might find that the voltages fluctuate within their given range and as you increase them this can cause instability. You will also find the power supply unstable if it is at the top of it’s power rating. Unbranded power supplies are usually a bit hit and miss, so use with caution. Personally I’m a fan of the Corsair range. They are well priced, pretty quiet, very reliable and deliver consistent voltages.

The coolers that come with the Intel chips are fine for everyday use, and normal thermal conditions. However, as overclocking increases the speed and voltages for the processor, it also increases the heat that is produced as a by product. This can be negated by installing an aftermarket CPU cooler. I won’t start suggesting coolers here, everybody’s requirements differ, some would rather a quieter cooler, and others one that cools better but at the cost of noise. So I suggest you read the reviews and work out which one suits you best.

Suggested Software

CPU-Z is the best way to find out everything about your cpu and system before you get started and is also often used in screenshot form as a proof of CPU speed.

For temperature monitoring you can use Core Temp, or Real Temp.

For stress testing there are a number of tools that you can use, I’ve had a lot of mileage out of Prime95, be aware that it comes in 32 and 64-bit versions depending on your system.

Getting to Know the BIOS

You can access the BIOS at boot (as the computer turns on), by hitting a designated key, it will usually tell you which. Del is common, as is F1.

Navigation in the BIOS is achieved with the keyboard, the mouse will not work. The cursor keys navigate you around, Enter takes you into a menu option, and Esc takes you back up a level. When you are done, be sure to save your changes. There will be a menu option to save and exit. If you do not want to save the changes that you makde then choose the exit without saving option

The BIOS is a place that you will be spending a lot of time if you intend to overclock your system, so take some time to move around all of the menus and find out what each item does. Ideally pull up a laptop and research each setting so you know exactly what it does. If this isn’t possible then write down the settings, or take a photo on your phone, reboot the system and go and research them. Each BIOS is a little different in the terms used and the location/ grouping of settings, so time spent here will give you the confidence to jump in and know exactly what the changes that you are making will affect.

Before you dive into the BIOS to overclock the chip, there are a set of options that should be set in a certain way to make sure that the rest of the system is as stable as possible when you start overclocking.

  • PCIe/ PCI, or on older systems AGP may also be mentioned. These should be set to locked.
  • Turn off any energy saving methods such as Intel Speedstep as this interferes with what we are trying to achieve.
  • It can be beneficial to set the RAM speed to lower than usual by changing he divider. This allows you to concentrate on the stability of the other components that you are tinkering with without worrying about the RAM being a cause of instability.
  • Do some further research on your components and set up. This step can’t be stated too many times. every single set up is different so you need to find out as much as you can about your components

Performing the Overclock

To start the overclocking process you need to increase the FSB. Having found where to do this, you increase it by a small amount (usually 5-10MHZ), save changes, see if you can start the system and run a quick stress test as mentioned above for 5-10 minutes. This shows you that the system is stable and you can continue.

When it gets to the point that you are either failing the stress test or are unable to boot the system then it’s time to think about the voltages.

If you have set your voltages to automatic (not recommended but it can be easier to start with) then you may or may not be able to overclock further by switching to manual. Otherwise, you need to drop the FSB a little to the last stable setting and commence further tests for up to 24 hours to prove that the system is stable.

If you have set the voltages to manual then you can now start to increase the voltages for the CPU and the NorthBridge in very small increments, You should now be able to increase your FSB. From this point it is a case of juggling the increases in FSB and voltage to see how far the system will go.

You might find that you get errors about hard drive corruption, or graphics errors. This is usually a good sign that you should increase the voltage on the Southbridge.

Do remember that this is an iterative process, you will likely have to keep making small adjustments repeatedly until you reach a stable point.The most important part is researching, gaining knowledge of your specific system and then testing before you continue to stability testing.

Stability Testing

Generally when you overclock you will find two levels that your chip can achieve. The top level is the highest that you can successfully boot with, and then slightly lower is what is usually called an everyday overclock. This is the highest that your components can stably run at 24/7. The former is more a test of the chip and just to see how high you can get it for bragging rights. The latter is obviously more useful as you can use it daily and gain significant benefits from having more power.

The stability testing is usually done with a system that performs calculations to stress the processor, such as calculating prime numbers. The idea is that the CPU is running at 100% for a long period of time, this allows you to see if it fails and freezes or crashes, which is common, or if it overheats with prolonged use. If either of these things happen then you are best off reducing the overclock to take account of this.


Hopefully I have pointed you in the right direction here and you use the article as a basis to continue to read up on the subject. If you do follow up on this then put your results into the comments below, I’d be interested to see how you did and what the results were. If you have any other tips or pointers why not add those into the comments as well, I’m sure that some people reading this have more different experiences to me and I’m always interested to hear them!