What You Need To Know About Overclocking

Part of the final frontier with PCs is overclocking: getting more out of your system than it says on the box. But what settings do you change? How do you overclock safely? And do you need to change anything at all, or can you get a program to do it for you?

If you’ve ever asked yourself any of these questions, never fear. Here’s what you need to know about overclocking.

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What is overclocking, exactly?

In simple terms, overclocking is the process where you tell your hardware to run at speeds above their stock, or default, manufactured rating. For a CPU, that might mean increasing its core multiplier (a CPU’s speed is always its base clock times the core multiplier). For graphics cards, that could mean increasing the core, memory and boost clock speeds to get better performance in games.

You can overclock your RAM as well; hell, if you’re so inclined, you can even “overclock” certain monitors to get higher refresh rates (something people used to do before 120hz/144hz/240hz gaming monitors became common place).

What are the pros and cons?

One of Australia’s best overclockers, Dino Strkljevic, going through the overclocking process with an Intel i7-5960X on a GIGABYTE X99 SOC Champion motherboard and lots of NO2

The simple reason: you can get more performance for free! Precisely how much of a boost you’ll be able to get comes down to how good your cooling setup is, what components you’re working with and how lucky you are, since no two parts overclock the same. But every computer can get at least some benefit from overclocking, which can result in your games running faster, video encoding taking less time, or highly complex tasks finishing earlier.

Of course, there are always consequences. The obvious downside is that by setting your gear to run at higher frequencies, you’ll get higher temperatures which can reduce the life-cycle of your gear. Precisely how much effect overclocking has depends on how hard you push your equipment: a CPU that’s only mildly overclocked with a slight adjustment to its core clocks will hang around longer than one that’s been running at higher voltages, higher base clocks, and so on.

If you push things too far you can make your system unstable, or damage your precious parts entirely. You have to be really determined to do this though: if your parts aren’t capable of running at the speeds or voltages you set, your system will crash or refuse to boot, which is generally an indication that you need to dial it down.

And if things do crash: don’t worry! You can always go into your PC case and reset the BIOS settings to normal, getting your machine back to a stable state. There’s also a suite of failsafes built into modern CPUs, GPUs, motherboards and everything else to prevent permanent hardware failure. And overclocking is a far simpler process in 2017 than it used to be: there legitimately was a time where you needed to draw lines on your CPU with a pencil to overclock a CPU.

And the reason why you should bother at all is because while you might reduce the overall lifespan of your system parts, you’re 99% guaranteed to upgrade your PC before your CPU/RAM/GPU dies out anyway. The general upgrade cycle for regular PC gamers is every three to five years, with only hardcore enthusiasts picking up parts before then (and usually it’s just a single upgrade, like a new GPU). Overclocking, therefore, is a good way to eek an extra bit of life out of a system before finally taking the plunge – and you don’t need to spend thousands on water cooling and custom blocks to give yourself the headroom you need.

It’s worth noting that overclocking will void your warranty. That said, manufacturers are pretty supportive of overclocking and will often have tips and advice on what to do, so don’t treat it like some kind of forbidden fruit. And as long as you stay within the recommended voltage range for your gear, and make sure your CPU isn’t running at temperatures above 75oC all the time, you’ll be right as rain. The extra performance in your system is there, so take advantage of it!

What do I need?

First thing you should do: clean your case out. This won’t be a problem if you’re just building a rig from scratch, but most people will be doing this with their current PC. And like most people, you’re probably lazy – which means your case has a good bit of dust stuck between the fans.

Overclocking any part means it will run a little hotter, and dust will only exacerbate the issue. Get a can of compressed air and blow that stuff out, and use a brush or a Q-tip to get between stubborn fan blades or the heatsink grill. You’ll need to take small breaks while you do this, as compressed air cans get cold fast, and they work best when they’re warm, or at room temperature.

Once you’ve case is all cleaned out, next thing you’ll want to do is have some materials on standby. Get your motherboard manual; it’ll explain what all the options are in your BIOS, and if anything it’ll at least point out where the CMOS reset button is if you can’t find it. (If things go awry, you’ll want to know where this is.)

Next thing you’ll want to do depends on what you’re overclocking specifically. To avoid overwhelming you with too much information at once, I’ll focus on two parts: the CPU and GPU. It’s possible to overclock other parts of your system as well, but those are the two parts where you’ll see the most benefit.

Another tip: make sure your power supply has the overhead to support overclocking! Most people buy more than they need when it comes to power supplies, and if you’re building a PC from scratch it is always worthwhile investing in a high quality power supply. The better the power supply, the more stable the supply of power to your computer. Having a decent quality motherboard is also important, as lower end offerings will be less reliable when it comes to overclocking. It’s more detail than is necessary for here, but if you want a more detailed explanation, GamersNexus has an excellent breakdown on how motherboards work.

Overclocking your CPU

You don’t need a setup this fancy to get into overclocking. Image: Kotaku

Before you start fiddling around with settings, the first thing you’ll want to do pre-overclocking is to check your cooler. Most medium to high-end CPUs don’t come with a stock cooler, so you’ll have to buy an after-market (or third-party) cooler. Coolers come in two parts: the heatsink, a series of metal grills that dissipate heat, and the fan, which intakes cool air and expels heat to keep temperatures down.

The good news: decent after-market coolers cost bugger all. Cooler Master’s Hyper 212X is a solid choice: it doesn’t look flashy, but it’s reasonably quiet, is well-built and does the job for $50. You can spend more, of course: high-end air coolers include Noctua’s gargantuan D-14 and D-15 coolers, or you could spend around $100 on a closed-loop water cooling system from Corsair.

The more you spend, the lower temperatures you can get from the off – and the further you can push your system. But the thing you have to remember is that overclocking any CPU (or GPU for that matter) is a bit of a lottery. No two systems are guaranteed to achieve the same results: you could get a chip that overclocks really well, and you could get one with no headroom at all. CPUs are only guaranteed to run at the clock speeds printed on the box, and anything you get beyond that is up to the silicon gods.

Something else you’ll want to have on hand pre and post-overclock is some monitoring software. These will tell you what your default, safe settings are (in case you needed them), and they’ll help you remember what your overclocking limits are. Importantly, they will also help you keep an eye on your system temperatures in real-time, a crucial tool for keeping everything stable.

The best part is all the great tools are free to download. CPU-Z is a good tool with plenty of information about your CPU, GPU, motherboard, RAM, and it has a couple of in-built stress tests to boot. HWMonitor will also help you keep track of the temperatures of everything in your system, as well as how much each piece of hardware is being utilised, how fast your system fans are running, and more.

You’ll also want to run some automated tests to get a sense of your computer’s base performance. This gives you something to measure, as well as giving you a mechanism to stress test your setup post-overclock. The CineBench 3D test is free to download, and the CPU-specific test is fairly widespread across the industry. Geekbench is another industry standard test that’s free to download, and both are handy to have not only to gauge your PC’s performance against the rest of the world, but to see whether your system will remain stable under extreme workloads. If you really want to be sure, however, Prime95 will push every core your CPU has to the absolute limit. A PC that can withstand a Prime95 test for several hours will pretty much handle everything.

So now that you’ve got all the basics down, it’s time to make a choice: do you use an automated tool, or do you overclock manually?

If you’ve never overclocked any part of a PC before, and have never seen a BIOS screen, you might want to opt for the former. Most motherboards these days will ship with some kind of software (on a supplied DVD or downloadable from the manufacturer’s website) that will automatically tweak your PC to run faster. Once it hits a point where it can no longer remain stable, the software is smart enough to save the last known settings that worked.

If you’re using an Intel CPU, Intel has its own software called the Extreme Tuning Utility. The tool has become commonplace amongst even hardcore overclockers, with a separate hall of fame on the HWBot competitive overclocking forums for records achieved with the software. Commonly referred to as XTU, the benefit of using the program is that it will be the same across every computer, whereas the software supplied by motherboard manufacturers is more varied.

The competitive overclocking community collaborated with Intel on XTU, and they put together a handy explainer on how it all works.

XTU comes with an in-built CPU and memory stability tests, and once you’ve established a baseline performance you can start playing around with your core clocks, CPU voltages, boost clocks and more. Precisely how much you can overclock will depend on what type of processor you have: any Intel series CPU with a “K” at the end has unlocked clock multipliers, meaning they’re more apt to achieve higher speeds than their unlocked variations out of the box.

It’s still possible to overclock non-K labelled CPUs, but it’s a little trickier since you have to adjust the CPU’s base clock – affecting the clock speed of your RAM in turn – and you have to boost the CPU’s voltage. That doesn’t mean you can’t get good speeds from a locked CPU, but it reduces the room your CPU has to manoeuvre.

If you’re sporting an AMD CPU, most likely from the brand new Ryzen line, then the software you’ll be dealing with is Ryzen Master:

Again, most of the stuff in here is pretty straightforward. Like XTU, the idea is to provide an interface that lets you control clock speeds and frequencies without having to enter into the BIOS.

Once you get the basics down, however, you’ll probably start to want finer control of how far you push your CPU. And for that, you’ll need to enter the BIOS. Got that motherboard manual handy? If not, go get it – it’ll help a great deal.

Much like with the software beforehand, the main settings you’ll be dealing with are the base clock speeds, clock multiplier and your CPU’s core voltage. You should already have the base settings written down (thanks to the monitoring tools outlined above), but if you haven’t, don’t stress. Every motherboard comes with a series of default and “optimised” default settings you can reload, and if things go awry you can always hit the reset CMOS jumper on your motherboard. Alternatively, you can remove and reseat the CMOS battery. All of these options will reset your motherboard back to default settings, and if this all sounds confusing, your motherboard manual will have an diagram showing you exactly where all of this is.

Most motherboard manufacturers will have a setting in their BIOS that lets you simply increase the core or boost clock speed of a CPU. GIGABYTE, for instance, have a setting in their BIOS called “CPU Upgrade” that lets you select a higher frequency depending on the CPU you have installed:

Other motherboards might also have “easy” or “Autotune” settings that will automatically bump up your CPU’s clock speed. Each manufacturer will lay things out differently, and some of them may have different features (or the same features worded a different way). Again, having the motherboard manual on hand will help here.

Regardless of the phrasing, every motherboard will have a range of advanced settings giving the user finer control of their overclocks. As to what settings you want to apply, it’ll come down to the exact brand and type of CPU you’re using. There’s too many variations to go into detail here, but the HWBot forums has specific sections for every CPU, motherboards for each CPU, and the settings people have used for both. You can also download a variety of profiles from the leaderboards to give you an idea of where to start – and what to do if things go wrong.

As for what CPUs are better for overclocking, Strkljevic adds that Intel’s K-series CPUs have been the most popular. “They make it easier to OC as you just have to change the CPU ratio multiplier. I would recommend starting with something on the lower priced side such as the 7350K or if money is no object [the] 7700K.” AMD’s Ryzen CPUs have become interesting of late, however, but what hardware you get will ultimately depend on your budget and your individual needs.

When it comes down to overclocking through the BIOS versus software, it depends on your needs. You’ll always be able to get a better result through the BIOS, veteran PC builder and indie developer Paul Nunez explained, and you’re also dealing with less layers between you and the hardware. “BIOS tweaking means getting the numbers and having less services running on boot up. Less RAM being used. And that all leads to something closer to the most optimal performance,” he said.

Dino Strkljevic, a world-class overclocker and current marketing manager at GIGABYTE, added that while overclocking software is good for getting a bit of overall performance generally, it might not be precise enough for your exact hardware. “Software OC is going to give you a reasonable ball park MHz overclock but it cannot account for your particular CPU silicone which could be a voltage loving CPU or one that does not like voltage [increases]. Every CPU OCs differently in a way so doing it manually will be more precise.”

For more information, hardware forums are the best place to go. One of the best is also one of Australia’s oldest: Overclockers Australia, a home for hardware enthusiasts all around the country. Plenty of advice is available on the HWBot forums as well, and both sites have special sections where beginners can ask for guidance.

Overclocking your GPU

Overclocking your GPU can often just be as beneficial as your CPU, but it comes with challenges of its own. GPUs often run at hotter temperatures out of the gate, especially if you’re relying on an air-cooled unit, which will limit the amount of gains you can get. The luck of the draw matters just as much with a GPU as it does a CPU, too. Two people could walk into a store and by the exact same model, and get completely different results.

If you’ve got a watercooled GPU, or you want to have a go and see what results you can get, there’s plenty of tools to help you out. You’ll need to rely on software to overclock your GPU – you can’t do it from the BIOS.

Like your CPU, you’ll want to run some tests beforehand to establish a baseline of performance. A common test is Futuremark’s 3DMark suite, which has a range of tests for all parts of your system. The benchmarks you’ll see most often are the Firestrike, Firestrike Extreme and Firestrike Ultra tests. (The latter two simply up the rendering resolution of the benchmark.) Other tests include the Unigine Heaven benchmark, the PassMark GPU benchmark and the GPU-focused variant of CineBench.

Once you’ve got that sorted, the next step is to look at overclocking the GPU itself. To stay on the safe side of things, you’ll want to stick to the core and memory clock speeds: GPUs are already pushed pretty hard, and mucking around with a GPU’s voltage is a good way to fry the card.

Irrespective of what software you’re using (like MSI Afterburner, EVGA Precision X, or your manufacturer’s software), you’ll want to increase the amount of power going to the GPU. 120% is a good place to start; you’re asking the card to run at higher speeds, and it’ll need a little more power to do so. For safety, you’ll also want to manually set your fan speeds to about 80% to handle the increased workload. Most tools will let you set a temperature limit as well: around 82oC or 83oC should do it. (Some cards also have profiles for the fans on the GPU itself: it’s recommended that you set those to match your desired maximum temperature too.)

Once that’s set, you can start boosting your memory and core clock speeds in small increments. Increase both by about 100Mhz, and then run the stress tests of your choice. Keep an eye on the temperatures as you go, and watch to see how the benchmark performs. Once you get to a point where the benchmark’s performance becomes unstable, you’ll want to drop the core or memory clock speeds down a notch. (You might also find that you can push a GPU’s memory speed a fraction more than the core clock speed, but just like CPUs, every card varies.)

Something worth remembering is that unlike the extreme CPU tests, like Prime95, games can push your GPU just as hard. Be a little more conservative when it comes to your GPU overclocks: it’ll often be the most expensive component in the system, and as Nunez pointed out, it pays to throw caution to the wind.

“Move in steps. Be gentle. Test often. Hitting a specific number for one benchmark or competition is different to making a really fast system; stability is of utmost importance,” he explained. “Ultimately: tweak, test, consider, repeat.”

He added that in some cases you can also improve the stability of your overclocks with a tiny increase of the card’s voltage. And you’ll be able to do this in the overclocking software of your choice, although you’ll have to dig through the settings to find it. “It’s very important to be very careful with, but not overlook, voltage,” Nunez said. “I’ve had some situations where a TINY over voltage to VRAM has allowed me to push further than I expected – and remain stable.”

So that’s what you need to know about overclocking. As with anything this precise and technical, there’s always more to learn and more information we haven’t covered. If you’d like to know more, don’t be afraid to ask questions – enthusiasts are always willing to help.

How much have you overclocked your systems in the past – and what advice would you give someone who has never overclocked a system before?

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