How to Overclock the i9-10900K: A Guide for Taming the Beast

Today we’re offering up some guidance for overclocking the 10-core, 20-thread Intel Core i9-10900K. We’ll cover what’s needed in a motherboard and more importantly, considering the heat this CPU can generate, what type of cooling you’ll require. We’ll also discuss different types of stability testing and their benefits or drawbacks, check if memory speed has an impact, and the different BIOS options we need to use in order to achieve a stable overclock. One last thing we’ll touch on is software overclocking in Windows. This guide can help you overclock any other in the offering of Comet Lake desktop processors as well.

The i9-10900K is the newest addition to the Intel mainstream CPU lineup and sits at the top of the product stack for good reason. This CPU has 10 cores that are able to run at 4.9 GHz at stock given the right conditions, but Intel has placed strict rules on these conditions. If they’re not met the CPU will throttle. To give you an idea of what we mean here: During the review process, we stress test CPUs with AIDA64 stability at default and FPU-only settings plus we hammer it with Prime95 small FFTs. When left at Intel’s default settings, the CPU would lower clocks and throttle because of the load. The frequencies we observed were 4.6 GHz in the AIDA64 stability test, 4.2 GHz in the FPU-only test, and way down to 3.8 GHz during our Prime95 small FFT test.  Most motherboards today are able to side-step these limitations in order to maintain a higher frequency like 4.9 GHz regardless of power usage. Many will do it automatically, but the motherboard we are using here today – the ASUS ROG Maximus XII Extreme requires MCE (multi-core enhancement) to be enabled, or select F3 in the BIOS upon first boot/CMOS reset.

The Motherboard

Choosing the right motherboard to suit your needs is critical as it is the foundation of your system, and skimping here can make a big difference. If your intentions are to run at stock then most likely any motherboard that supports your LGA 1200 CPU choice will do. Overclocking, on the other hand, requires a motherboard with a Z490 chipset, a beefier VRM power section, and options in the BIOS to make the necessary adjustments for optimizing your system. We’re not saying that you need to get the best of the best in order to overclock, but a poor choice here can hold things back. Luckily, most mid-range motherboards today can handle the added stress of overclocking.

Motherboard choice is also a personal thing depending a lot on your uses. Does it have the required USB or SATA/M.2 connections for your purposes? Some people gravitate toward looks and RGB LEDs and the ability to coordinate a light show in their case. My personal choice is always a motherboard that focuses on overclocking. It’ll have what I need for everyday use and I’m not really into the bling so whatever it has is fine. I’m also an extreme overclocker so having LN2 (liquid nitrogen) options is a must, and I also like some of the added buttons such as Mem OK and Safe Boot which can reset the BIOS without losing my settings.

One thing for certain, you will need to know how to reset or clear your BIOS. Using the F5 or F6 (depending on the brand) key while in BIOS is a good way to refresh all your settings and start with a clean slate (Many boards call this Optimized defaults). There are times while overclocking you’ll find yourself in a position where the system will not boot because of the settings you have tried. On some boards, there are buttons as I mentioned earlier but all of them have the ability to clear the CMOS either with a button or a set of jumpers so consult your manual here as you will need it. Clearing the CMOS removes all your settings and returns the BIOS back to its original state, but all of your settings will be lost so saving your progress along the way is highly recommended.

If you’re not certain what motherboard choice is suitable for your needs you can always ask our members here on Overclockers.com in out Intel motherboard section.

We are including a list of some Z490 motherboards and prices that we could find, this isn’t a recommendation list but illustrates what’s available in your price range.

Originally published May 29, 2020. Prices updated July 1, 2022.

Cooling

Your cooling choice will depend on your goals but at a minimum I would recommend a 240 mm All-in-One or high-end air cooling if you intend to run the i9-10900K at anything but Intels recommended 125 W TDP. As you can see in our review of the i9-10900K, using a 240 mm EVGA AIO was enough to run the CPU at 5.0 GHz while stress testing with Prime95 small FFTs. Moving up to the EK Predator 360 mm CLC we were able to squeeze another 100 MHz from the 10900K but the temperatures were still creeping over 90°C and the TjMax for this CPU is 100°C at which point this motherboard will throttle the CPU and reduce its speed. The only other option at this point is custom water cooling which can be quite costly but they are effective. We also have more exotic cooling such as dry ice, phase change machines, and LN2 but that’s not really in the scope of this article.

Monitoring Software

When overclocking you will need some type of software to monitor your system while stress testing. Keeping an eye on the temperature of the CPU is vital, luckily motherboards and processors in this day and age have safety precautions built-in and will throttle the CPU in order to protect it from catastrophic damage. The i9-10900K will throttle once the temperature reaches 100°C. At that point, the CPU reduces the temperature but at the cost of clock speed which is not something you want when trying to get the maximum performance from your system.

There are many options out there for monitoring your system, most motherboard manufacturers will have their own proprietary software such as AI Suite from ASUS. Many of these, like AI Suite, have the ability to overclock your CPU while in Windows but we’ll get to that later. Here’s a list of some common programs that are available, as you’ll see later in some of the screenshots I prefer HWinfo64 as it provides more information than most will ever need.

• Core Temp–  Monitors CPU temperatures– Free
• HWInfo64– Monitors full system, temperature, voltages, and throttling–Free
• HWMonitor– System monitor– Free/Paid
• Open Hardware Monitor– System Monitor– Free

Some software offers more than just monitoring options like AIDA64 for example. AIDA64 can be used for free with some limitations but offers monitoring for the system, memory benchmarks, and stability testing for memory and the CPU. We’ll also include Intel XTU here, this utility can overclock your CPU as well as benchmark, stress test, and monitor your CPU vitals.

Stability Testing

Before we get to overclocking, we need to evaluate different stability testing techniques and software. This is a contentious subject in enthusiast circles. How much stability is enough and is there a trade-off between added performance and stability. My answer is always no, your system is either stable or it isn’t. There really is no in-between and if you need absolute stability then don’t overclock at all.

My system, which to date has proven to be very effective is a one hour test with Prime95 small FFTs which really hammers the CPU, requires the most voltage, and produces the maximum heat for evaluating your cooling solution. After the initial testing is successful, it’s on to Prime95 blend test with Unigine heaven running in the background for four or more hours. This isn’t nearly as stressful on the CPU, but it also incorporates the memory and graphics card for full system stability testing. It will also test your setup’s ability to remove heat from your case which often gets overlooked when people are overclocking. If heat builds up in the case because of poor ventilation, the system, no matter how stable, will eventually crash or throttle from the excessive temperatures.

One of our members put together a small write up a few years ago, although a bit dated it’s still relevant to stability and “level” of stability which may be right for you. I don’t necessarily agree with everything, but as was mentioned this is a highly debated subject in the forums. This is Trents’ explanation of stability and he also goes over many of the tests which can be used. One last thing, many in the forums have been using Cinebench R20 as a stability gauge, CB R20 is a benchmark, not a stability test. Even though it will crash an unstable system, the test is way too short to claim a truly stable system.

Regardless of what you use to test stability after overclocking, keep in mind that aside from the obvious signs of an unstable system, such as blue screens and complete system crash to desktop, there are more subtle signs such as WHEA (windows hardware errors) entries that if left unchecked will eventually corrupt your operating system. This is why we always recommend that when overclocking it’s best to use a separate HDD/SSD with an Operating System that can easily be reinstalled. If you’re building a new system, complete your overclocking and stability testing before installing your applications or transferring data from older drives.

We’re including a list of stability testing software with links below:

• Intel XTU– Tuning, monitoring, benchmarking, and stability
• AIDA64– Monitoring, benchmarking, and stability
• Prime95– Stability
• Realbench– Benchmarking, and stability
• Intel Burn Test (IBT)- Stability
• OCCT– Monitoring and stability

Test System

BIOS

Later we’ll touch on software overclocking, but for now, we’re going to concentrate on the BIOS and hopefully clear up a bit of the mystery that can intimidate some users. The BIOS (basic input/output system) is a program that initializes and controls the hardware, but also acts as a traffic manager between different devices such as your CPU, storage, graphics card, etc… in a nutshell, without the BIOS the PC can’t function. What we’re interested in today are the various hardware controls needed to overclock the CPU and the naming of these options. The latter can be a bit hard to pin down since the BIOS nomenclature isn’t standardized and varies by vendor. We’re using an ASUS motherboard today but the naming will be similar on others if not the same. All of the settings we will use today are located in the Extreme Tweaker section of the Extreme’s BIOS.

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The first thing we need to do is get into the BIOS. This is done during the POST cycle by hitting the Delete or F2 key, with today’s UEFI BIOS and Windows 10 you need to be quick or you’ll end up in the OS. Here I’ll run through, in order, what I do to begin overclocking. Once in the BIOS, I set  XMP (eXtreme Memory Profile) to get the memory running at its rated speed and set MCE to enabled. MCE is an ASUS option that bypasses the Intel operating limits and needs to be set for overclocking. Many boards do this automatically and do not have a BIOS option.

After saving and booting to Windows the i9-10900K will be running at 4.9 GHz under an all-core load which will make some heat. The first step in any overclocking attempt should be a baseline run. This is done for two reasons, first, it evaluates the performance of your cooling solution. Secondly, it will give you a starting point for voltage settings in BIOS. Just remember that the voltage is currently on auto so there can be some variance.

After a short test with Prime95 small FFTs, as you can see in the picture above, we have plenty of room left for cooling and the voltage reading is a bit over 1.26 V at 4.9 GHz. Now we’re ready to start overclocking so let the fun begin.

Overclocking the i9-10900K: BIOS

Before we get started there are a couple of things that should be mentioned here. Overclocked settings are unique to your system and testing techniques. What this means is finding someone else’s settings on the internet then plugging them into your BIOS most likely isn’t going to work very well, so take the time and do it properly as every CPU and setup is different. Also, overclocking is a process, when done correctly start with the baseline and work up from there 100 MHz at a time testing and evaluating after each change. Doing things slowly will also prevent you from overwhelming your cooling which will result in throttling.

Now that we have our baseline we can go back to the BIOS and begin. As was mentioned earlier the BIOS will differ by the vendor, but ASUS has all the important settings contained in the Extreme Tweaker section. We need to set the multiplier (CPU Ratio) manually, scrolling down we’ll stop at “CPU Core Ratio” and set this to “Sync All Cores” which locks all cores to the same speed. Next up is the “All-Core Ratio Limit”, here we’re going to use a multiplier of 49 which is the same as our baseline speed. We’ll also want to set the “AVX Instruction Core Ratio Negative Offset” to zero which will prevent the system from throttling when it encounters AVX instructions.

On our way to the voltage settings, we’re going to make a quick pit stop in the “Digi+” section. This opens up a new menu that holds a lot of settings that we won’t be using. The one we do want is called “CPU Load-line Calibration”. If you reference the BIOS pics above you’ll see that on this particular motherboard they recommend “Level 4” when overclocking. Setting the LLC isn’t always necessary and varies by the motherboard. What it does is help limit the drop in voltage (Vdroop) you may experience when the CPU is under load which can aid in stabilizing an overclock. Hitting ESC brings us back to the Extreme Tweaker menu and we’re ready to continue.

Moving on to voltage, we’ll set the voltage manually, but first, we need to open up that option by highlighting the “CPU Core/Cache Voltage” and selecting the “Manual” option from the drop-down list. Right below this, we can now input our desired voltage by highlighting “CPU Core Voltage Override” and typing 1.3 in the entry field then hit enter. I chose 1.3 V as a starting point since it was higher than what we observed in the baseline run and cooling isn’t a concern at this point so a bit extra won’t put us over the top. Save and Exit then allow the system to boot to Windows.

Back in windows we’ll check our manual settings the same way by stress testing and monitoring the thermals. These settings passed easily so we rebooted back into the BIOS. At this point, you may want to navigate to the “tools” section and save this profile. We’re not done overclocking but this will leave you a good starting point just in case things go off the rails and it’ll save you from having to input all the changes again. Now we’re going to up the multiplier from 49 to 50, boot into Windows, and test again. This time, however, the system crashed likely due to the V_Core being too low.

Back to the BIOS to add some voltage. Since we still have quite a bit of headroom for cooling I went straight to 1.35 V for the Core then saved and exited booting into Windows again. This time the testing went well and we managed to run Prime95 small FFTs for 10 minutes, thermals were good, so we decided it was time to get the next 100 MHz.

While in the BIOS this time we upped the multiplier to 51 and since we needed approximately a 0.05 V increase the last time going from 4.9 to 5.0 GHz we set the CORE voltage to 1.4 V and proceeded to test again. This test also ended in a system crash after a few minutes, our thermals were acceptable so we went to the BIOS and added a bit more voltage to 1.41 V. This time the test lasted over 20 minutes before it failed so I knew we were close. One more increase for the voltage to 1.42 V and we had a successful Prime95 small FFT test for over an hour at 5.1 GHz. As you can see in the picture below, the temperatures were creeping over 90°C indicating that we were out of cooling headroom and we’re unable to proceed any further, 5.1 GHz was going to be the end of the line.

As I mentioned earlier I’m a stickler for stability and many may consider what I do a bit excessive but I have used this method for years and it hasn’t failed me yet. Using a “less stressful” stability test will result in higher overclocks as we will see in the software overclocking section to follow but your system may not be able to handle very CPU intensive tasks. For now, we’re going to continue into what I like to call my system stability test. This next part is particularly useful in testing the efficiency of your case cooling and whether or not it can evacuate the hot air from the CPU and GPU combined.

Using the previous settings, we change to the Prime95 Blend test which will now include more memory and cache in its calculations. In the background with Prime95 Blend churning away, we have started the Unigine Heaven benchmark running in a loop. Unigine Heaven is a good benchmark to get your GPU hot and the combination of the two will produce a lot of heat. If you can successfully finish four hours of this type of testing you know you have a well-balanced system. If not, somewhere along the line the system will crash and odds are you need to evaluate the ventilation in your case since it’s not exchanging the air well enough.

Overclocking the I9-10900K: Windows

Whether you’re overclocking AMD or Intel CPUs there is software available to do so in a Windows environment. There are also software overclocking alternatives offered by motherboard manufacturers. The ROG Maximus XII from ASUS has two alternatives AI Suite III and TurboV which we’ll have a look at today. We’re also going to run through an overclock using Intel’s own Extreme Tuning Utility (XTU) which will work regardless of which Z490 motherboard you choose.

ASUS AI Suite III

AI Suite has been around for many years and has matured into an all-in-one interface incorporating many ASUS utilities into one GUI. The part we are interested in for overclocking is called TPU (TurboV Processing Unit) which gives control over the CPU speed and related voltages needed for overclocking. ASUS has also incorporated AI Overclocking into the AI Suite but from my experience, it still needs a bit of work- as you can see from the example below.

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ASUS TurboV Overclocking Software

TurboV is another overclocking utility from ASUS, this one is very lightweight and not overly intrusive. This software, in my opinion, is perfect for extreme overclockers trying to squeeze those last few MHz out of the CPU for competitions. When overclocking under extreme conditions, such as liquid nitrogen, you always reach a point where you just can’t boot to Windows with the CPU running that fast. We’re talking speeds of 7.0 GHz or higher and we’re constantly on the edge of stability. Using TurboV we can boot into the operating system at a lower speed and use the utility to increase the speed and voltages afterward. That being said, you could use it daily but the overclock doesn’t apply at Windows startup as it will with AI Suite or Intel XTU but needs to be loaded from a saved file.

Intel XTU

The Extreme Tuning Utility from Intel is a well-rounded application that can overclock, stress test, monitor, and benchmark your CPU. The interface is easy to use and the overclocking options are very extensive but as with BIOS overclocking we only need a few of them.

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Overclocking via software in Windows is just like overclocking in the BIOS in that you need to test the system stability after every change to the multiplier or voltages. Since we knew we had a super stable overclock using 1.42 V at 5.1 GHZ we just started with those settings. Using the built-in AVX2 stress test at 5.2 and 5.3 GHz with the same voltage the system seemed stable. First I tested these settings with Cinebench R20 and it passed at 5.3 GHz.

I’m not certain what kind of magic XTU was working in the background but I do know that 1.42 V wasn’t enough to pass CB R20 at that speed when setting in the BIOS. If you look to the voltage section you’ll see that at idle the voltage is now going over 1.5 V but under load, we’re seeing 1.34 V during the benchmark. Running high voltage can degrade your CPU over time but I would be more concerned about the load voltage which does seem reasonable.

We continued testing the overclock we achieved using XTU, this time running Realbench. I chose a short test of 15 minutes using 8 GB of RAM for a quick check and it passed easily and CPU temperature maxed at 86°C which is well within its thermal limits. I will add that starting the Prime95 small FFT test instantly crashed the PC at these settings, but as I said earlier, many feel that Prime95 is overboard for the average user.

Cache and Memory Speed

This comes up fairly often in the Overclockers.com forums, “Does faster memory help with gaming?”. In general, faster memory and cache make little difference in most situations, gaming being one of them. Some games may benefit but the majority see a 1-3% increase in performance and at the end of the day, it’s going to make very little difference visually. Now, someone who is benchmarking competitively is going to squeeze every inch of the CPU and memory even if it is for a 1% boost since every point counts here.

We have a few examples of benchmarks that have been run at different RAM and Cache speeds just to show the gains you can expect. We took our stable overclock of 5.1 GHz and upped the cache speed to 4800 MHz from the stock speed of 4300 MHz as well as swapping the RAM for two 8 GB sticks of 4000 MHz Cl17 DDR4. Just to verify stability we tested it again and ended up adding a bit of voltage ending up at 1.43 V. Increasing the cache speed most often requires a bit more voltage since it feeds off the same rail as the CPU core.

Aside from the CPU core voltage the VCCSA and VCCIO voltage will also need an increase to accommodate the faster RAM – these two voltages help stabilize the IMC (internal memory controller) and input/output of the CPU, respectively. Many motherboards will adjust these accordingly when installing faster RAM modules as the Max XII Extreme did, raising them from 1.15 V to 1.35V. This may seem a bit high but attempts to reduce them resulted in a boot loop and required clearing the CMOS to get the system started. There are occasions where these voltages will need some manual tweaking so keep that in mind if you decide on a high-speed RAM kit or a large quantity of RAM.

This first shot is a baseline run with our initial overclock settings at 5.1 GHz for comparison.

For this next one we have raised the cache speed from 4300 to 4800 MHz. As you can see bumping up the cache speed made little difference in FSE but the CB R20 benchmark gained about 100 points.

Now we have added in the 4000 MHz Cl17 RAM with the 5.1 GHz overclock and 4800 MHz cache. Overall, there are increases of approximately 100 points in Fire Strike Extreme and CB R20 but it’s really no reason to feel like you’re missing out with 3200 MHz RAM.

Overclocking the i9-10900K: Conclusion

That pretty much wraps things up. Whether you choose to overclock through the BIOS or Windows the process is the same. Stability and thermal overload need to be addressed through extensive testing and slight adjustments here and there. In the end with some patience, you’ll be rewarded with years of performance, and, if done right, Windows will keep chugging along without issue (at least not from overclocking). If you have any questions or concerns you can always post in our forums at Overclockers.com. We have some very knowledgeable members who are always happy to help out a fellow enthusiast even if this is your first time. Remember – there are no stupid questions!

Happy overclocking!

Shawn Jennings – Johan45

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