CPU Buying Guide


Overclocking is a popular pastime for PC enthusiasts, and involves squeezing additional performance out of a CPU by altering the frequency at which it is run. Clock speed is a combination of the Front Side Bus speed of the motherboard and the clock multiplier of the CPU. By altering either the FSB or clock multiplier, you can, in theory, up the overall frequency of a given processor. To do this, you need overclocking to be supported on both the processor and the motherboard.

The most common way to stop users overclocking is to lock the clock multiplier of a given CPU. Manufacturers have played around with how difficult it is to alter clock multipliers on their CPUs, and don't officially condone the idea, although it's worth noting that the current high-end CPUs, such as the Intel Core 2 Extreme, come with no lock on the clock multiplier.

In CPU manufacturing, manufacturers first test each CPU at the theoretical maximum speed it's capable of. If it passes, it's sold as a premium-priced, high speed chip. If it fails, it'll be tested at lower speed, and sometimes with specific functional operations disabled, until it's either running in a stable form -- and sold as a lower speed chip -- or junked altogether. From the manufacturer's point of view, the fewer chips they have to junk, the more profitable a given run of CPUs will be.

Because of this manufacturing economy, there is scope for overclocking chips, but be careful. No CPU manufacturer offers warranty support for overclocked chips, as there's a distinct danger of overheating a chip by running it faster than it's been safely clocked at. After all, if it ran well at that higher speed, it would be sold to market as a higher speed chip. Overclocking enthusiasts try to get around the increased heat output by changing the cooling arrangements within a PC to dissipate the extra heat. This can range from simply putting on a slightly larger heat sink and fan than the vendor supplied CPU fan all the way up to water-cooled semi-frozen PCs running at much higher speeds than would seem sensible.

Join the Good Gear Guide newsletter!

Error: Please check your email address.

Our Back to Business guide highlights the best products for you to boost your productivity at home, on the road, at the office, or in the classroom.

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

PC World Staff

PC World
Show Comments


Lexar® JumpDrive® S57 USB 3.0 flash drive

Learn more >

Microsoft L5V-00027 Sculpt Ergonomic Keyboard Desktop

Learn more >


Lexar® JumpDrive® S45 USB 3.0 flash drive 

Learn more >


HD Pan/Tilt Wi-Fi Camera with Night Vision NC450

Learn more >

Audio-Technica ATH-ANC70 Noise Cancelling Headphones

Learn more >

Lexar® JumpDrive® C20c USB Type-C flash drive 

Learn more >

Lexar® Professional 1800x microSDHC™/microSDXC™ UHS-II cards 

Learn more >


Back To Business Guide

Click for more ›

Most Popular Reviews

Latest News Articles


GGG Evaluation Team

Michael Hargreaves

Windows 10 for Business / Dell XPS

I’d happily recommend this touchscreen laptop and Windows 10 as a great way to get serious work done at a desk or on the road.

Aysha Strobbe

Windows 10 / HP Spectre

Ultimately, I think the Windows 10 environment is excellent for me as it caters for so many different uses. The inclusion of the Xbox app is also great for when you need some downtime too!

Mark Escubio

Windows 10 / Lenovo Yoga

For me, the Xbox Play Anywhere is a great new feature as it allows you to play your current Xbox games with higher resolutions and better graphics without forking out extra cash for another copy. Although available titles are still scarce, but I’m sure it will grow in time.

Kathy Cassidy


First impression on unpacking the Q702 test unit was the solid feel and clean, minimalist styling.

Anthony Grifoni


For work use, Microsoft Word and Excel programs pre-installed on the device are adequate for preparing short documents.

Featured Content

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?