Last Updated: Feb 28, 2018
In this complete introduction to CPU overclocking you'll learn everything you need to know including the reasons why you should consider clocking your processor, the parts needed to overclock a CPU, how CPU overclocking actually works, and the different ways/methods you can go about it including step by step guidance.
Benefits of Overclocking Your CPU
When you think of overclocking, you probably think about the processor. The benefits of overclocking your CPU past its stock clock speed include:
Whilst those reasons sound all well and good, sometimes overclocking a CPU isn’t worth it.
For example, if you’re building a new PC, instead of getting a weaker CPU and planning to overclock it to the level of a more expensive chip, you may very well be better off just buying the better CPU from the get-go and not overclocking.
Overclocking requires you to invest money into an aftermarket CPU (and the further you push a CPU the better the cooler you’ll need), and a better PSU and motherboard.
So overall, planning to overclock may not be the more cost-effective route compared to simply getting a better non-overclockable CPU.
Another reason not to overclock a CPU, not including the general cons of overclocking explained in module 1, is that modern top-tier processors generally don’t benefit all that much from an overclock as they’re already supremely fast.
You will see an improvement in speed, but whether that extra little boost is worth it or not is completely subjective.
Overall, we’d generally only recommend overclocking your CPU if you’re using a mid-tier processor and already have a decent motherboard and PSU, as mid-tier CPUs will generally see the most gains.
Alternatively, go ahead and overclock if you’ve got a high-end system with high-quality parts and you care about every extra ounce of processing power for CPU-intensive games and non-gaming applications.
Choosing Parts for Overclocking
Choosing a CPU for Overclocking
To overclock a CPU you need to have a CPU model that has an unlocked multiplier. Basically all AMD CPUs have this and Intel CPUs that have a “K” on the end of the model number such as the Intel Core i5-7600K which is a popular choice among the overclocking crowd these days.
As mentioned earlier, the best candidates for overclocking are mid-tier CPUs as they offer the most performance benefit; top-tier CPUs will still receive a boost but it won’t be as noticeable of a jump as with a mid-tier model.
Choosing a CPU Cooler for Overclocking
You’ll also require a third-party/aftermarket CPU cooler (ie HSF: Heatsink and Fan), as the stock coolers that come shipped with CPUs aren’t designed to handle the extra heat that overclocking brings.
Plus, some CPUs that are designed for overclocking (such as the i5-7600K) don’t even come with a stock cooler anyway as it’s assumed you’ll get your own.
At the very least, for basic to moderate overclocking, you’ll to get something like the Cooler Master 212 Evo or Arctic Freezer 7 which is two excellent-value, popular models within the overclocking community.
For higher-end processors and with more intense overclocking you’ll want something even more effective such as Noctua’s range of coolers.
You also have the option of getting a liquid cooler, which are technically referred to as AiO (All in One) liquid coolers. A couple of popular examples are Corsair’s Hydro and NZXT’s Kraken series. Liquid cooling is even more effective than air cooling but comes at an added cost.
In general, the more you spend on your cooler, the lower the potential temperatures you can get, the further you can push your system, and the safer overclocking will be.
Then finally, if you’re wanting to go all-out with overclocking and you want the absolute best possible cooling solution possible (and you have the time, interest, and money) then you may wish to consider setting up a custom water cooling loop.
It’s not necessary, especially with the presence of good AiO coolers and many great air coolers on the market, but nothing beats a custom water cooling setup when it comes to keeping temperatures low during intense overclocking, and minimizing (or obliterating in some cases) noise, but there are the downsides of the extra complexity, cost, and potential for things to go wrong with your system (and a little extra maintenance).
It’s also recommended to get and apply some good quality thermal paste to your cooler such as the popular and high-quality Arctic 5 paste for maximum cooling efficiency. Some aftermarket CPU coolers may come with paste already, but many enthusiasts prefer getting their own to be sure of quality and reliability.
Choosing a Motherboard for Overclocking
On top of having a CPU with overclocking capability and an aftermarket CPU cooler with thermal paste to handle the extra heat, to overclock a CPU you’ll require a motherboard that supports overclocking. For Intel motherboards you’ll need a board with a Z-rated chipset, which means looking for a “Z” in the model number such as the Asus Prime Z270-A.
As for AMD, any motherboard should work for overclocking, however you’ll want to lean towards a high-quality board that is designed for overclocking as not all boards are created equal when it comes to pushing your CPU; read reviews and others’ experiences with overclocking on certain boards (same goes for Intel boards mind you).
Pushing your parts with an overclock increases the amount of power flowing through your motherboard to the CPU. That power is transmitted by what’s called the voltage regulator module (VRM) on your motherboard.
Ideally you want a board that has a VRM with high-quality, leak-resistant capacitors, good-quality chokes, and ideally a heatsink/fan over the MOSFETS (Metal-Oxide Semiconductor Field-Effect Transistors).
Cheaper motherboard won’t have these features, so for overclocking you want to ideally get a higher-quality (and almost always more expensive) motherboard.
Choosing a Power Supply for Overclocking
Another thing to think about is your power supply. Because overclocking increases the power output, you’ll want to be sure your power supply can handle the added requirements of your overclocking adventures. If you built your PC wisely, this shouldn’t be an issue as you should have planned ahead and got a PSU with wiggle room.
As well as having enough power, you’ll want to ensure your PSU is at least a fairly reliable model with good reviews from trusted sources. Ideally, stick to the best PSU brands around such as Seasonic, Silverstone, XFX, or top-tier models from Corsair, Antec, and EVGA.
Whilst not always an indicator of reliability, getting an 80-plus rated unit (either Bronze, Silver, Gold or Platinum) is highly recommended as it means it’ll be an efficient unit. Also research what sort of rails you will need, as not all PSUs are created equal.
The last thing you want to do is push your components hard with a low-quality unreliable PSU as it could possibly blow your PSU and other parts in the process, so do your research and read professional reviews, too.
How Overclocking a CPU Works
Before diving in and getting your hands dirty, it’s a good idea to review the basic principles of how overclocking a CPU actually works, and to look at the 3 main methods you have to choose from and how to decide which strategy to go ahead with.
Overclocking a CPU is basically adjusting the clock speed of the CPU, which is the measurement of how quickly the processor switches from one cycle of instructions to another and is measured in gigahertz (GHz).
The clock speed is not the only determining factor of the overall speed of a CPU but it’s the most well-known and important one.
The clock speed of a CPU is actually calculated by taking what’s known as the base clock speed (abbreviated as BCLK) of your motherboard, which could be 100 MHz for instance, and multiplying that by the CPU’s multiplier which is just a single number such as 35. In this example, the CPU clock speed is 3500 MHz or 3.5 GHz.
What you actually do when overclocking is either increase the base clock or the multiplier, either via entering the motherboard’s BIOS software or using another software program (such as automated motherboard software, Intel XTU, or Ryzen Master).
By changing either the multiplier or the base clock speed, the CPU clock speed is therefore recalculated at a new speed.
So for example, if we change the multiplier from 35 to say 38 that means the clock speed will now be 3.8 GHz instead of 3.5 GHz.
Back in the day it was more common that you would alter the base clock, but modern overclocking is all about tweaking the multiplier (sometimes called the Core Ratio) until you get a faster, stable speed.
Also, keep in mind the increase in CPU speed requires more power consumption, which can cause system instability if you don’t take precautions. The solution is manually adjusting the CPU’s core voltage (VCORE) to maintain system stability which we’ll also cover later.
When it comes to overclocking your CPU by changing the multiplier, which is the way we’ll be covering it in this guide, you’ve got three choices to get it done:
The rest of this module will cover each of these three CPU overclocking methods, including a look at the pros and cons to each method to help you decide between them for your own situation
Preparing to Overclock a CPU
Before we get into the actual overclocking methods, there are some universal things to do before diving in that apply no matter which method you use.
Step 1: Clean Your Case
Because overclocking increases the heat generated by your CPU, you not only want to have a good CPU cooler as mentioned earlier, but you’ll want to also make sure your case airflow is on-point.
That means getting rid of dust, so unless you’ve just built a brand new PC build from scratch, open up your case and clean it out with a can of compressed air or special computer vacuum.
Use a soft long-bristle house-paint brush or cotton swab/bud to clean hard to reach areas. Don’t forget to remove dust on your case fans so they’re in peak condition, and clean any dust filters or grills that your case has.
Step 2: Backup Important Data
Before tinkering with your system you want to backup any important files that are on your PC because you never know what could happen if things go bad; while highly unlikely these days, there is the possibility of damaging your hard drive.
Step 3: Other Considerations
Before following any of the steps outlined in this guide, a wise move would be to read ahead before actually applying anything you learn so you can anticipate what’s to come and take that into account.
Don’t just blindly follow steps listed here, or in any overclocking tutorial for that matter. Consider whether it applies to you, plan ahead, and move slowly and methodically through any sort of overclocking process.
CPU Overclocking Method #1:
Automatic Overclock with Built-In Motherboard Overclocking Software
If you’re brand new to overclocking and also a hardware beginner that has never changed a single setting in a BIOS before, you might want to consider starting with this method as it’s the easiest, less-risky, most beginner-friendly way to get your feet wet with overclocking.
Many modern motherboards will come with some automatic overclocking software either provided on DVD or downloadable from the manufacturer’s site, and these programs will increase the performance of your CPU until your system becomes unstable, at which point the software will automatically restore the last working settings.
The Asus Prime Z370-A pictured below (and currently included in our extreme gaming builds at the time of writing this) is an example of a modern motherboard with included overclocking features:
These automatic performance optimization programs are usually fairly straightforward to use and can work well at times depending on your motherboard and your CPU, but they don’t always produce the best results.
Also, they tend to be less precise, and as well as not giving you the best speed increases they may increase your CPU voltages higher than necessary.
If your motherboard has this type of software, and you want to give it a shot, then refer to your motherboard manual which should be all you need as it is the most simple way to overclock after all.
CPU Overclocking Method #2:
Manual Overclock in the OS
Let’s move onto the next level of CPU overclocking, which is using manual overclocking software in your operating system (as opposed to entering your BIOS).
Whilst not the ideal way to manually overclock, as nothing beats heading into your BIOS/UEFI for maximum control and results, this method is quite a bit better than using automatic motherboard software, and simpler and less tedious than using the BIOS.
Another benefit that overclocking in your operating system has over using the BIOS is it’s universal. Meaning, it’s the same process on different PCs, and the same interface. When using a BIOS to overclock, the process can differ quite a lot from motherboard to motherboard.
In terms of which software you should actually use to overclock manually in your OS, you want to stick to the official programs provided by the processor manufacturers. For Intel users that would be Intel’s Extreme Tuning Utility (XTU), and for AMD you have Ryzen Master if you’re using their modern Ryzen range of processors.
Learn more with our step by step guides to each method:
CPU Overclocking Method #3:
Manual Overclock in the BIOS/UEFI
Out of all three main ways you can overclock a processor, entering into the holy BIOS is the most complicated yet it gives the most control and potential for good results.
If you’re a total beginner and just wanting to get your feet wet with overclocking, I’d advise you to stick to Intel XTU/Ryzen Master or even your automatic motherboard overclocking.
But if you do want to venture into the potentially murky BIOS waters read on to learn the basics of how this works and some general good practices.
I say general good practices because it’s tough to give specific guidance when overclocking in the BIOS because the process is unique to different systems and CPUs.
Different CPUs, motherboards and memory setups will have their own nuances to look out for and will produce different results.
There isn’t a universal way to approach this, but there are some basics and general best practices that apply no matter what your particular setup is.
But manual overclocking is a process that needs to be undertaken slowly and methodically, with plenty of testing and monitoring along the way to ensure you have decent system stability and you don’t damage or severely reduce hardware lifespan, corrupt your operating system over time, or create other complications.
Refer to your motherboard/BIOS manual to see what they say about overclocking with your particular board.
I’m not trying to scare you off from the BIOS, as once you get the hang of it it’s really not that bad or complicated, but I just want to warn you that it’s not for those who just want to dabble in overclocking for an afternoon.
You’ve got to be willing to dedicate some time to doing it slowly, methodically, and safely, although to be fair that applies no matter which way you overclock.
The good news about BIOS overclocking though is that these days the modern BIOS is usually a lot easier to navigate than text-only versions of the past. Many now have graphical UI’s that you can control with your mouse.
Learn more with our guide: How to Overclock in the BIOS
NEXT: GPU Overclocking 101
A hobbyist game programmer turned hardware enthusiast, Julien "cyberjulz" is the founder of BGC and has kept a keen eye on the latest in DIY gaming ever since starting BGC back in '06 as an almost laughably-basic and brief 20 page site with the aim to make building PCs more accessible to the average gamer since most resources weren't too noob friendly. Over countless reinventions and reiterations to the quality, depth and usefulness of the content over many years the site has steadily grown into the expansive, comprehensive and ever-updated first-time PC builder resource that it is today that now reaches and helps thousands of gamers and power users each month to more easily plan optimal setups for their exact needs. You can learn more about the BGC mission and ways to support it here.
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