Learn to fulfil your processor’s potential in 10 simple steps
Before crossing the start line, there’s a few basic principles to get your head around. The first one is heat. Inevitably, the more voltage you add to your components, the more heat that component is going to output. Second, the higher the clockspeed you’re trying to achieve, the more voltage you will need to power that attempt. And thirdly, there’s only so much voltage your PC part can take before you start to see detrimental effects. These could be a drop in frame rates for GPUs, corrupting processes on the CPU, or even a failure to boot at all. These, essentially, are the basic limits of overclocking.
All chips are born equal, but some are more equal than others. You’ll often hear overclockers talk of ‘The Silicon Lottery’. In short, this is to do with the manufacturing process with each and every processor. Small imperfections in the application of the silicon lead to a variance in how well the chips perform, both in stability with an increase in voltage, and how much heat they produce at max load. You might get lucky with yours, or you might not. It can equate from anywhere between 0.2GHz difference to, in some cases, up to 1GHz in overclocking potential.
So, assuming you’ve got an aftermarket cooler of some description (see “Picking a Cooler” below), that you have a processor or component that’s capable of overclocking (K/X series for Intel and any AMD chip), and that you understand how to get into your BIOS, here’s how to get going.
1 Checking CPU stability
To ensure a successful overclock, we’ll need to know that the CPU is stable at both idle and max load. To do this, we’ll be using a free piece of software called Prime95, from http://bit.ly/1kVNJZh. You’ll also want to download a program to accurately monitor the temperatures your CPU is outputting. For this we’ll use Core Temp, from www.alcpu.com/CoreTemp/, as this works with both AMD and Intel cores. There are alternatives out there – Corsair and NZXT have proprietary software that works with their AIOs, plus most motherboards have viewable temperature controls that you can use from the desktop. If you don’t fancy installing anything on your rig, then Real Temp GT is your guy.
2 Core temp
Once those programs are extracted or installed, load Core Temp to begin monitoring your CPU’s temperature. Always look at the lowest core temp to give yourself a good understanding of how hot your CPU is running.
3 Stress tests
Now we’ll want to benchmark your CPU, at stock, to see how hot it runs at 100 per cent. Start Prime95, select ‘Just stress testing’, and then you’ll be given a list of options as to which stress test you’d like to perform. Choose ‘Blend Test’ and press ‘OK’.
4 Into the BIOS
After about 5-10 minutes, once your temperatures have stabilised, go into Prime95. Select ‘Test’ on the top bar and hit ‘Stop’, then restart your PC and mash that [Delete] key to get into your BIOS. In this test we’re using an ASRock Z97 Extreme 4 motherboard, so the UEFI could be a little different in comparison to some of the other manufacturers you’ll find out there, but the base settings will essentially be the same.
5 Auto-overclock
Once inside your BIOS, find the overclocking tab. In ours it’s named ‘OC Tweaker’. Once in, you have several options. The easiest way to overclock your CPU is to let the motherboard do the majority of the work. Most manufacturers will include overclock profiles, usually ranging from 4GHz to 4.8GHz, depending on the CPU installed.
Setting the motherboard to run one of these profiles will allow it to attempt to overclock the chip to that frequency without any user input. This can be a quick solution, especially if you’re only dialling in a conservative overclock (3.5GHz to 4GHz, for example), but this isn’t conducive if you want to push beyond that 4.8GHz barrier, or if you can’t reach that frequency through the automated profiles.
6 Changing the multiplier
More adept users will find manual control a lot more comprehensive in regards to what true overclocking is all about. To keep it simple, you want to be changing the CPU ratio, or multiplier, for all cores to the target number you wish to achieve. That’s 35 in this case. The multiplier then works with the cores’ BCLK frequency (usually 100) to create that final figure of 3.5GHz. In this tutorial, we’re going to attempt to overclock our CPU just to start with from 3.5 to 4GHz, simply by changing the multiplier.
7 Test at max load
Once you’ve changed the CPU ratio multiplier to 40, save changes and exit the BIOS. Boot into Windows, open Core Temp to monitor your CPU temp, then open Prime95 and select ‘Options’, ‘Torture Test’ and finally ‘Blends Test’, to see how your chip fairs at max load. If it’s stable for at least five minutes, we can begin to up the multiplier to achieve a higher overclock.
8 Finding the limit
At this point, you’ll want to increase the multiplier by one and repeat the process of stress testing in Windows each time, until you reach the point where you initially either blue screen or your CPU begins to thermally throttle itself. Ideally, you want to blue screen before you reach your thermal limit.
9 Increasing the voltage
To overcome the blue screen issue, we need to start working with the Vcore voltage. Back in the BIOS you want to find CPU Vcore Voltage Mode. Change this to ‘Fixed’. At this point you may need to do some research as to what the stock Vcore your CPU takes, and what people are suggesting for overclocking. You’ll want to begin increasing the voltage by 0.01 volts each time, until you can successfully boot, stress test and maintain stability at your target frequency. Once you get a little more comfortable overclocking, you’ll find yourself increasing voltages by 0.05 or 0.1 at a time. It’s more about learning how your CPU responds to different amounts of voltage at this point.
Eventually, you’ll reach a point where you cannot reach that next frequency, regardless of how much voltage you throw at it. This is when you want to dial back your overclock by 0.1GHz and drop the Vcore voltage back to the last stable settings for that frequency and maintain it there, as this is your final overclock.
10 Back to benchmarking
To ensure a stable overclock, you should now benchmark for as long as you feel is appropriate. This can be anywhere from an hour to a full day, depending on how patient you are.
Picking A Cooler
The first thing to consider after you’ve decided on overclocking is what you’ll use to cool your components. To put it bluntly, the stock coolers that AMD and Intel provide simply won’t cut it when it comes to dissipating the excess heat that comes from adding more voltage. They’re designed to deal with what the processor can output at stock frequencies, and not a lot more.
Air
The more traditional, easier solution would be to rely on air cooling for your CPU. There’s a huge list of air coolers out there, from a wide variety of brands, but it’s vital that you consider the size of the cooler versus the height of your RAM and the size of your case. The last thing you want is to buy a new heatsink for your shiny new i7-4790K, only to discover it won’t fit over the top of your Corsair Dominator GTs. The Dark Rock Pro 3 is a particular favourite of ours – it’s silent, yet can effectively relieve your CPU of over 250W of TDP, plus it’ll keep your bacon cool.
AIO water cooling
The second option is an all-in-one water cooling loop. You’ve probably seen a lot of these kicking about – Corsair’s Hydro H100i being the more famous of the bunch. These are a quick and easy solution, and often provide a great deal more cooling than a single air cooler, due to their increased surface area. They’re also a lot less finicky to install (providing you have the radiator support), and can clean up your rig quite nicely while allowing you to swap out components with relative ease.
Custom-loop cooling
Finally, the elephant in the room, the fully custom loop. It’s the dream, the crème de la crème, and the aspiration of every tech enthusiast starting out on the bumpy road to a successful overclock. It’s also something that’s become increasingly easy to build in recent years. Although certainly the most effective of the three, due to the ability to expand on your loop by adding more radiators, and cool more components, it can become very rigid, especially if you want to change out a graphics card, for example. It’s definitely something that needs to be researched fully before committing to, if only because it can easily add £400 to your costs. And that’s with the cheapest components out there. But wow, does it look good when you’re done. The Parvum Titanfall rig is a prime example of this.