If you’re looking to extract the maximum possible performance from your CPU, you’ll need to overclock. This is a process through which a processor is forced to run faster than it otherwise would. It provides gamers and other power-users with a means of making the latest cutting-edge components even more impressive. It also allows us to push older CPUs that little bit further, thereby eliminating performance bottlenecks in GPU-heavy systems. Many people overclock for the sake of doing so – after the release of most high-end CPUs you can always find a roomful of enthusiasts pushing the new hardware to 7GHz and beyond, with the help of outlandish cooling. Here, we’re going to look at how an absolute beginner can get started on their journey to a faster overclock.

How is Overclocking Done?

You can manipulate your CPU’s speed in one of a few ways. We’ll start with the most obvious method.

Automatically

A great place to start is to take advantage of your motherboard’s automatic overclocking functions. Motherboards vary in their overclocking abilities, but if you’ve bought a reasonable gaming motherboard, you should expect to see all sorts of helpful features in the BIOS.

Navigate to your BIOS configuration by holding the appropriate button (usually Del) as your machine boots, then navigate to the overclocking tab. You’ll typically be confronted with a short list of built-in profiles, tailored for your chip of choice. Now, given that every CPU is slightly different, there’s no way for a motherboard manufacturer to know exactly how far a given chip can be pushed, even if the exact model of CPU is known.

A minor overclock can often lead to a noticeable improvement in performance. But if you want to really push things you’ll need to delve a little deeper by overclocking manually.

Manual Overclocking

Two numbers govern the ultimate clock speed of your CPU. The first is the base clock, and the second is your multiplier – multiply the two and you get your total clock speed. Some chips, built with overclocking in mind, come with unlocked multipliers. In Intel chips, this is most often indicated by a ‘K’ at the end of the chip’s name.

Shifting up the multiplier is the safest and most straightforward way to overclock your CPU. We’d suggest bumping it up by around 10% to begin with (so if you’re at 40, try 44). Once you’ve established a stable overclock, you can look at going higher in increments. If your CPU lacks an unlocked multiplier, you might instead look to shift up the base clock. Depending on the age of your machine, doing this might shift up the speed of the entire Front Side Bus, which means that your RAM and any PCIe lanes will be similarly affected. This is, in most cases, not worth the effort, as many of the other components to which your CPU is connected might not cope with being pushed beyond their base rates.

How do you Test an Overclock?

To see whether an overclock is stable, you’ll need to push the CPU to its absolute limit. This is one of the functions performed by Prime95, a program initially developed to calculate really, really big prime numbers. Prime95’s Torture Test will test the limits of your CPU in a way that no normal program ever would, and is an excellent way to establish whether your machine can cope with your new overclock. If it’s stable while Prime95 is running, then it’s going to be capable of dealing with just about every other job your system might throw at it.

What Restricts an Overclock?

Of course, it’s not possible to overclock a CPU indefinitely. At some point, you’re going to run into failure in one form or another. Whichever method of overclocking you choose, you’ll run into two adverse effects, one of which is in part caused by the former:

Voltage

As you force a CPU to do more, it’ll use up more power. When there isn’t enough power available, it’ll start to misfire. What this means technically is beyond the scope of this article – but in practice, insufficient voltage will summon the dreaded Blue Screen of Death. This is a safety mechanism built into Windows which stops all processes, displays a code detailing the reason for the failure, and then restarts.

Modern CPUs are a great deal more power-efficient than older ones, and so they’ll remain stable even without the support of an expensive motherboard. However, at some point you’ll need to go into the BIOS and shift up the voltage to keep your overclock stable. We’d suggest doing this in increments of 0.01 volts until you’re comfortable making the changes. And this, in turn, will create more heat.

Heat

There’s a reason that chunky, liquid-based aftermarket CPU coolers are almost obligatory if you’re going to be overclocking significantly. When you crank up the speed, you’re also going to generate more heat. More heat means greater resistance, which not only increases the likelihood of an error but also shortens the lifespan of your CPU. It’s for this reason that the record-breaking overclocks come as a result of sub-zero cooling systems involving canisters of liquid nitrogen.

Finding the Best-Possible Overclock

As you work your way up, increasing clock speed and voltage, you’ll eventually come to a standstill, and you won’t be able to stress the CPU, no matter how much extra voltage you give it. Take things back a few hundred MHz and pull back the voltage. You’re almost done, but you’re not ready to wrap up. You still need to test the overclock and make sure that it’s stable enough for everyday use. Do this by benchmarking for as long as your patience allows – we’d suggest leaving it overnight, and then checking it when you return from work the following day. If you don’t have a blue screen after that, the chances are that you never will!