The University of Massachusetts Amherst
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CPU Overclocking: Benefits, Requirements and Risks

The Benefits of Overclocking

Overclocking is, essentially, using the settings present on the motherboard in order to have the CPU run at higher speeds than what it’s set to run by default. This comes at the cost of increased heat production, as well as potential reduction of lifespan, though for many people the benefits far outweigh the risks.

Overclocking allows you to basically get ‘free’ value from your hardware, potentially letting the CPU last longer before it needs an upgrade, as well as just generally increasing performance in high demand applications like gaming and video editing. A good, successful overclock can grant as much as a 20% performance increase or more, as long as you’re willing to put in the effort.

Requirements 

Overclocking is pretty simple nowadays, however, there are some required supplies and specifications to consider before you’ll be able to do it. For most cases, only computers that you put together yourself will really be able to overclock, as pre-built ones will rarely have the necessary hardware, unless you’re buying from a custom PC builder.

The most important thing to consider is whether or not your CPU and Motherboard even support overclocking. For Intel computers, any CPU with a “K” on the end of it’s name, such as the recently released i7-7700k, will be able to overclock. AMD has slightly different rules, with many more of their CPUs being unlocked for overclockers to tinker with. Always check the specific SKU that you’re looking at on the manufacturer’s website, so you can be sure it’s unlocked!

Motherboards are a bit more complicated. For Intel chips, you’ll need to pick up a motherboard that has a “Z” in the chipset name, such as the Z170 and Z270 motherboards which are both compatible with the previously mentioned i7-7700k. AMD, once again, is a bit different. MOST of their motherboards are overclock-enabled, but once again you’re going to want to look at the manufacturer’s websites for whatever board you’re considering.

Another thing to consider is the actual overclocking-related features of the motherboard you get. Any motherboard that has the ability to overclock will be able to overclock to the same level (though this was not always the case), but some motherboards have built in tools to make the process a bit easier. For instance, some Asus and MSI motherboards in particular have what is essentially an automated overclock feature. You simply click a button in the BIOS (the software that controls your motherboard), and it will automatically load up a fairly stable overclock!

Of course, the automatic system isn’t perfect. Usually the automated overclocks are a bit conservative, which guarantees a higher level of stability, at the cost of not fully utilizing the potential of your chip. If you’re a tinkerer like me who wants to get every drop of performance out of your system, a manual overclock is much more effective.

The next thing to consider is your cooling system. One of the major byproducts of overclocking is increased heat production, as you usually have to turn up the stock voltage of the CPU in order to get it to run stably at higher speeds. The stock coolers that come in the box with some CPUs are almost definitely not going to be enough, so much so that Intel doesn’t even include them in the box for their overclockable chips anymore!

You’re definitely going to want to buy a third party cooler, which will run you between 30-100 dollars for an entry level model, depending on what you’re looking for. Generally speaking, I would stick with liquid cooling when it comes to overclocks, with good entry level coolers like the Corsair h80i and h100i being my recommendations. Liquid cooling may sound complicated, though it’s fairly simple as long as you’re buying the all-in-one units like the Corsair models I mentioned above. Custom liquid cooling is a whole different story, however, and is WAY out of the scope of the article.

If you don’t want to fork over the money for a liquid cooling setup, air cooling is still effective on modern CPUS. The Coolermaster Hyper Evo 212 is a common choice for a budget air cooler, running just below 40 bucks. However, air cooling isn’t going to get you the same low temperatures as liquid cooling, which will not let you get as high of an overclock unless you want to compromise the longevity of your system.

The rest of the requirements are pretty mundane. You’re going to want a power supply that can handle the higher power requirement of your CPU, though to be honest this isn’t really an issue anymore. As long as you buy a highly rated power supply from a reputable company of around 550 watts or higher, you should be good for most builds. There are plenty of online “tier-lists” for power supplies; stick to tier one or two for optimal reliability.

The only other thing you’ll need to pick up is some decent-quality thermal compound. Thermal compound, also called thermal paste, is basically just a grey paste that you put between the CPU cooler and the CPU itself, allowing for more efficient heat transfers. Most CPU coolers come with thermal paste pre-applied, but the quality can be dubious depending on what brand the cooler is. If you want to buy your own, I recommend IC Diamond or Arctic Silver as good brands for thermal compound.

Risks

Overclocking is great, but it does come with a few risks. They aren’t nearly as high as they used to be, given the relative ease of modern overclocking, but they’re risks to be considered nonetheless.

When overclocking, what we’re doing is increasing the multiplier on the CPU, allowing it to run faster. The higher we clock the CPU, the higher voltage the CPU will require, which will thus produce more heat.

Heat is the main concern of CPUs, and too much heat can lead to a shorter lifespan for the chip. Generally speaking, once you’re CPU is consistently running at above 86 degrees Celsius, you’re starting to get into the danger zone. Temperatures like that certainly won’t kill your CPU immediately, but it could overall lower the functional lifespan.

For most people, this won’t really be an issue. Not many people nowadays plan on having their computer last for 10 years and up, but it could be something to be worried about if you do want to hold onto the computer for awhile. However, as long as you keep your temperatures down, this isn’t really something you need to worry about. Heat will only outright kill a CPU when it exceeds around 105 degrees Celsius, though your CPU should automatically shut off at that point.

The other main risk is voltage. As previously mentioned, in order to achieve higher overclocks you also need to increase the voltage provided to the CPU. Heat is one byproduct of this which is a problem, but the voltage itself could also be a problem. Too high voltage on your CPU can actually fry the chip, killing it.

For absolute safety, many people recommend not going above 1.25v, and just settling for what you can get at that voltage. However, most motherboards will allow you to set anything up to 1.4v before notifying you of the danger.

My personal PC runs at 1.3v, and some people do go as high as 1.4v without frying the chip. There really isn’t a hard and fast rule, just make sure to check out what kind of voltages people are using for the hardware you bought, and try to stick around that area.

Essentially, as long as you keep the CPU cool (hence my recommendation for liquid cooling), and keep the voltages within safe levels (I’d say 1.4v is the absolute max, but I don’t recommend even getting close to it), you should be fine. Be wary, however, as overclocking will void some warranties depending on who you’re buying the CPU from, especially if the CPU ends up dying due to voltage.

Afterthoughts – The Silicon Lottery

Now that you understand the benefits of overclocking, as well as the risks and requirements, there’s one more small concept; the silicon lottery.

The silicon lottery is the commonly used term to describe variance in CPU overclocks, depending on your specific CPU. Basically; just because you bought the same model of CPU as someone else doesn’t mean it will run at the same temperatures and overclock to the same point.

I have an i7-7700k that I’m cooling with a Corsair h100i v2. I am able to hold a stable 5ghz overclock at 1.3v, the stock settings being 4.2ghz at around 1.2v. However, not everyone is going to achieve results like this. Some chips might be able to hit 5ghz at slightly below 1.3v, some might only be able to achieve 4.8 at 1.3v. It really is just luck, and is the main reason that overclocking takes time to do. You can’t always set your CPU to the same settings as someone else, expecting it to work. It’s going to require some tinkering.

Hopefully, this article has helped you understand overclocks more. There are some risks, as well as some specific hardware requirements, but from my perspective they’re all worth the benefits.

Always remember to do your research, and check out a multitude of overclocking guides. Everyone has different opinions on what voltages and temperatures are safe, so you’ll need to check out as many resources as possible.
If you do decide that you want to try overclocking, then I wish you luck, and may the silicon lottery be ever in your favor!