What is Overclocking a CPU? Lenovo FAQs. What is overclocking a cpu

The safe voltage for most AMD processors should not exceed 1.4V, but we recommend that you research your specific processor to make sure it isn’t set too high.

Overclocking for Newbies

Overclocking refers to pressing the computer’s components harder and faster than their manufacturer designed. The initial jump is seductive: buy a slower, cheaper CPU; increase clock speed; and presto! You have a cheap, high-end processor.

Of course, it is not that simple. Overclocking it can certainly speed up your system (and save some cash in the process), but only if you do it right.

We’re going to talk about some of the basics of overclocking – what it really is, the basic math behind overclocking, and how you can push your system a little harder and faster. The goal is to get better, stable performance for your money. After all, it doesn’t matter how fast your computer runs if you have to wait for a restart after a crash every 10 minutes.

While tweaking is a complex topic, we’ll try to keep the discussion here as simple as possible. We won’t go into detail about voltage fluctuations or power issues, or explore the intricacies of memory timing. And we are not going to show you how to get a cheap Celeron up to 8.2 GHz.

However, we’ll talk about CPU core multipliers and memory clocks, and how they relate to each other. Memory and processors are intricately intertwined, and simply increasing the speed of one or the other may not produce the desired performance improvements.

What Is Overclocking?

Microprocessors. Simply put, overclocking means setting your CPU and memory to run at speeds higher than their official speed class. Almost all processors ship with a speed rating. For example, the Intel Core i7 860 out of the box runs at 2.80 GHz. Overclocking the Core i7 860 means overclocking it to more than 2.80 GHz. In this article, we will mainly focus on CPU overclocking to illustrate the basic concepts (pun intended).

Processors do not melt immediately after overclocking them, because modern processor speed ratings determine the speed at which each processor is running in the same production batch – a number that is likely to be well below the maximum speed that a given processor is capable of.

Overall, the performance of the processor is now so good that the nominal speed class locked in the chip can be significantly lower than the speed at which the chip is able to boot the computer. In other words, since the statistical distribution in the manufacturing process is skewed towards better quality chips, the chances are that your CPU is better than its rated speed.

Before you begin, download and install the latest BIOS firmware for your motherboard from the manufacturer’s website. This is an important step to make sure you have the latest configuration options and that your efforts are not frustrated by known issues.

What is overclocking?

Overclocking is the term for increasing a component’s CPU (CPU or hardware) to speed up its performance. Increasing the clock frequency causes the component to run at a higher speed and perform more operations per second. Overclocking maximizes the speed and performance of your computer beyond the factory settings.

Many gaming enthusiasts, for example, want to exceed the factory-set CPU speed to build a highly efficient gaming PC. CPU overclocking gives you a more responsive PC and starts your hardware as fast as possible. However, not all processors can be overclocked. Standard CPUs may have locked multipliers that prevent people from making changes to the CPU to overclock. Some processors with unlocked multipliers are specially available for the overclocking enthusiast looking to assemble the fastest PC.

Since increasing the CPU speed speeds up the computer, the CPU will also generate excess heat. The additional heat that is generated can damage the computer, which is not countered by adequate cooling and extra care. Remember that modern computers and laptops have become so advanced and powerful that overclocking may not even produce noticeable results.

Overclocking works differently for all CPUs, but first make sure your system has adequate and extra cooling. Standard processors manage heat with a factory heat sink and fan. An aftermarket heat sink can further mitigate the excessive heat from overclocking, while an upgraded fan can release additional heat and increase airflow.

Water cooling is the optimal and efficient cooling option. The water-based coolant absorbs the heat and then the radiator pumps it out. After installing the cooling system, increase the clock frequency in the computer’s BIOS (Basic Input / Output System).

Gradually increase the clock frequency (or voltage), each time checking system stability and monitoring the computer’s temperature. Reduce it back to a stable level when it reaches an unstable level or maximum temperature. Avoid overclocking by large amounts at once.

How does overclocking work?

Overclocking is about increasing a computer’s CPU (central processing unit) to increase its performance beyond what it was designed for. An overclocked desktop computer can perform more operations per second due to the increase in the clock frequency of the component. In the computer’s BIOS (Basic Input / Output System), setting a higher clock frequency increases the processor speed and provides a faster, more responsive computer.

Your computer’s processors are factory-set to maximum speeds and adequate cooling to ensure stable operation. The factory heat sink and fan enable the standard processor to safely manage heat generated in normal use. However, overclocking overclocks these limitations to make your PC run faster. Not all processors can be overclocked due to locked multipliers that prevent modification. However, some processors are designed for enthusiasts such as gamers who want to use overclocking to build the most powerful PC with maximum performance.

To overclock or exceed the standard CPU speed limits, gradually increase the CPU clock speed by small amounts in your computer’s BIOS. With each increase, the stability and temperature of the computer should be monitored. A one-time drastic increase in processor speed can permanently damage the processor. Safe overclocking also requires an additional appropriate cooling system to handle and release the additional amount of heat generated.

While overclocking can produce a powerful PC, it’s important to remember that many modern computers and laptops are built with technologies so advanced that they are capable of producing the same better results as overclocking.

There are limits to how much more a user can apply to the CPU. If you use too much, you can damage the circuits. Usually this is not a problem as most motherboards limit this setting. Overheating is a more common problem. The more you provide, the higher the CPU’s thermal power.

What to Remember Before Overclocking

Your mileage may vary depending on the process. Every chip is different, and just because one person has some spin doesn’t mean you’ll be able to hit the same levels – even if you have the exact same CPU (hence the term “silicon lottery”). Also, your motherboard may not have all the features needed to achieve a really good overclock.

This guide is an overview of the process, but don’t be afraid to do more research into your motherboard, CPU, and what they can handle. Looking at other people’s overclocking performance can give you a decent position to shoot at, but you’ll still have to go through the process step by step to find the perfect settings and what your chip is capable of.

Step 1: Start With ‘Stock’

Before overclocking, it’s a good idea to get a reference point where your computer is located with no extra frequency. So restart your computer and enter the BIOS – this usually involves pressing “Delete” or “F2” while booting the computer.

Please take a moment to familiarize yourself with the BIOS and familiarize yourself with the different categories of settings. (On some motherboards, such as our Asus, you may need to go to “Advanced Mode” to find most of the features we’ll be using today.) Each motherboard manufacturer has a different layout and may even name some settings with different names. If you are ever unsure what our motherboard setting is called, google it and you should have no trouble finding a match.

After the terrain is shaped, look for an option called “Load Optimized Defaults” – usually near the “Save and Exit” feature. This will reset the BIOS to the bone stock settings, which is a good place to start. However, you may want to do some additional research on your motherboard – some boards have “auto overclock” settings turned on by default, which you can turn off before continuing.

Lastly, go to the Boot menu and make sure your PC is configured to boot from the correct hard drive (if you have more than one) – it may have reset after reverting to optimized defaults. Then select “Save and Exit” in the BIOS. Your computer restarts into Windows.

Overclocking the AMD CPU is very similar to Intel chips, but the software is different. If you have had an AMD Ryzen processor since 2017, the software we recommend for beginners is Ryzen Master. You can download the tool from AMD here.

Bus Speeds and Multipliers

All CPU speeds are based on two different factors: bus speed and multiplier.

The bus speed is the core clock frequency at which the processor communicates with components such as memory and the chipset. It is commonly rated on the MHz rated scale, referring to the number of cycles per second it operates. The problem is that the term bus is often used for various aspects of a computer and is likely to be lower than what the user expects.

For example, the AMD XP 3200+ processor uses 400MHz DDR memory, but the processor uses the 200MHz FSB, the clock of which is doubled to use 400MHz DDR memory. Likewise, the Pentium 4 C processor has an 800MHz FSB bus, but it’s actually a four-pumped 200MHz bus.

The multiplier is the actual number of processing cycles that the processor will complete for one bus speed clock cycle. So, a Pentium 4 2.4 GHz “B” processor is based on the following:

133 MHz x multiplier 18 = 2394 MHz or 2.4 GHz

When overclocking your CPU, these are two factors that can affect performance. Increasing the bus speed will have the greatest impact as it increases factors such as memory speed (if memory is running synchronously) and processor speed. The multiplier has a smaller effect than the bus speed, but may be more difficult to adjust.

Here is an example of three AMD processors:

Processor model Multiplier The speed of the bus CPU clock speed
Athlon XP 2500+ 11x 166 MHz 1.83 GHz
Athlon XP 2800+ 12.5x 166 MHz 2.08 GHz
Athlon XP 3000+ 13x 166 MHz 2.17 GHz
Athlon XP 3200+ 11x 200 MHz 2.20 GHz

Here are two examples of overclocking an XP2500 + processor to see what the nominal clock frequency would be by changing the bus speed or multiplier:

Processor model Overclocking factor Multiplier The speed of the bus CPU clock
Athlon XP 2500+ Increasing the bus 11x (166 + 34) MHz 2.20 GHz
Athlon XP 2500 + Increasing the multiplier (11 + 2) x 166 MHz 2.17 GHz

As overclocking was becoming a problem on the part of some unscrupulous dealers who overclocked lower value CPUs and sold them as more expensive CPUs, manufacturers started implementing hardware locks to make overclocking more difficult. The most common method is locking the clock. Manufacturers modify the traces on the chips so that they only run at a certain multiplier. The user can overcome this protection by modifying the CPU, but it is much more difficult.

Managing the Voltage

Each part of a computer has a specific voltage for its job. During the overclocking process, the electrical signal may degrade as it passes through the circuits. If the degradation is sufficient, it can cause system instability. When overclocking the bus speed or multiplier, the signals are more prone to interference. To remedy this, you can increase the voltage of the CPU core, memory or AGP bus.

There are limits to how much more a user can apply to the CPU. If you use too much, you can damage the circuits. Usually this is not a problem as most motherboards limit this setting. Overheating is a more common problem. The more you provide, the higher the CPU’s thermal power.

Intel XTU can look a little intimidating at first given the many very detailed options. But once you become familiar with the tool, it all makes sense. Information risks are becoming very useful.

AMD: Ryzen Master

If you have the latest generation AMD Ryzen CPU and you want to overclock it with as little effort as possible, you can use the automatic overclocking tool ClockTuner from 1usmus. If you’d like to learn how to manually do this to better understand what AMD overclocking is, follow the steps below.

Overclocking the AMD CPU is very similar to Intel chips, but the software is different. If you have had an AMD Ryzen processor since 2017, the software we recommend for beginners is Ryzen Master. You can download the tool from AMD here.

For older AMD processors, we recommend AMD Overdrive instead. The instructions below still apply, but the software layout is slightly different. Be sure to double-check what you are doing before making any changes.

Step 1: Stress test

Before you start overclocking your CPU, make sure it doesn’t exceed safe temperatures. While the Ryzen Master has a stress test built in, it doesn’t last very long. Instead, we recommend the AIDA64 Extreme utility and its stability test (free trial). If you like this tool, the full license is $ 40 and covers up to three computers.

Open it and select Tools from the top menu, then Stability Test. Press Start when you are ready and leave the computer for about an hour. Make sure the temperatures do not exceed 80 degrees at any time during testing. If so, please improve your CPU cooler before trying to overclock. If you have some temperature reserve, move on to overclocking the system.

Step 2: Frequencies

The latest Ryzen Master software is full of options, most of which aren’t needed for basic overclocking. To keep things simple, make sure you’re in Basic View. If your software matches the screenshot above, you’re all set. If not, select Basic View in the lower left corner of the expanded interface.

First, switch the control mode from Default to Manual. This will allow you to manually adjust the clock frequency and voltage that will be needed for overclocking.

Unlike Intel software, you can directly adjust the clock frequency instead of using a multiplier. Increase the CPU clock speed by 50 MHz, then select Apply and Test. The Ryzen Master will crank up your CPU’s frequency and test it. If your PC is stable and the temperature isn’t too high – again, the goal is to keep the temperature below 80 degrees – you can go through the same process again. Increase the clock frequency by 50 MHz, run a stress test and check that everything is cool and functional.

The built-in stress-testing tool in Ryzen Master is decent, but we recommend that you run the test through AIDA64 once you’ve hit your desired speed. Run the test again for about an hour and pay close attention to your temperature.

Continue this process until you reach the speed you want or a crash occurs. Then set it back to the last stable setting and use your computer for several hours (and maybe even a day or two). If it crashes again, please undo it and retest. When it’s able to run under stress all day, it’s your basic overclocking that you can fine-tune for a little bit of extra speed with voltage control.

The second pair is the new Intel Core i7 875K processor with unlocked clock – top tier Intel Socket 1156 processors – running on the Asus P7P55D-E Pro which costs around $ 190. The Core i7 875K is easy to overclock and can spike to extreme clock speeds quite easily.

Check for stability

Once you’ve hit the limits of what you can achieve by increasing your multiplier, it’s time to make sure your machine is still 100% stable. Prime95 is a great load testing tool for CPUs – if your overclocked clock can last ten minutes with Prime95, chances are your new clock speed is really solid. Start CPU-Z (to check that the clock frequency remains constant) and Prime95, selecting a small FFT when the Torture Test screen appears.

Run the torture test for at least ten minutes, then when you are satisfied with the stability of the chip, you must click the Test tab in the Prime95 window and manually stop the test. Simply closing the window will not necessarily do the trick.

You should now have some solid CPU overclocking, hopefully it will at least raise the game’s minimum FPS and potentially release some extra performance from graphics cards as a whole.

There must be more to it than that….

Of course it is. If you want to go even further with your expensive silicone, there’s a rabbit hole here that you can jump into. Get to the elbow with CPU overclocking and you can start fiddling with voltages and base clock settings, but doing so comes with a greater long-term risk to your hardware and a much more complex manipulation of different BIOS settings. Besides, tinkering with voltages also increases heat generation and may only slightly increase the clock frequency. You can also increase the BCLK of some CPUs, but this is more prone to failure.

You can improve the cooling of the CPU and the entire computer, which can help you achieve a higher end clock speed. If you’re using the same stock cooler that came packed in a CPU box, your chip will probably be more baked than it needs. Choosing the best gaming motherboard paired with a solid cooler can also be helpful.

Processors do not melt immediately after overclocking them, because modern processor speed ratings determine the speed at which each processor is running in the same production batch – a number that is likely to be well below the maximum speed that a given processor is capable of.

Benchmark, then boost

Now that we’ve covered the basics of overclocking, I’m sure you’re wondering what settings to try on your own PC! Because every processor is unique, there are no standard overclocking settings to ensure it works on every computer. Time for experiments!

Let’s summarize the goal. We want to achieve the fastest CPU speed on a PC that stays cool and stable. By stable, I mean it is doing POST (completes the test when powered on), boots to the operating system, and then successfully passes the stress test.

My advice is simple. Benchmark and then reinforcement. Then compare again and then reinforce. And so on. Test your computer in an overclock-free condition to understand the baseline voltage, temperature, and clock frequency. Then increase the fundamental clock frequency and / or the multiplier to get a slight boost (say 0.2 GHz). Restart your computer and run the benchmark again to see if it’s stable. If so, repeat the top-up and benchmarking test. If not, reverse the target settings a bit (or raise the voltage) and try again.

Overclocking can be a laborious process, but this safe, step-by-step approach helps you get a good understanding of your CPU’s capabilities.

There are many applications that you can use to compare your CPU. Geekbench is a popular choice, as are PCMark and Cinebench. Most of them are commercial applications, but they offer a free trial version.

I will be using Geekbench 4 today along with the great CPU-Z monitoring application which gives me all the voltage and speed details I need. I use the CAM NZXT app for temperature monitoring, but you may prefer an alternative like SpeedFan or another app that comes bundled with your motherboard.

Here’s a snapshot of the CPU-Z before overclocking the CPU. The numbers in the screenshot look static but are constantly updated depending on the CPU load.

Terry Walsh / IDG

Pay attention to the section Core voltage and clocks. The latter displays the overall CPU speed and multiplier. Regarding CPU temperature, when idle my CPU runs at a reasonably cool 32 degrees C.

Open Geekbench 4 (or any application of your choice) and run the Basic CPU Performance Test.

For accurate results, leave the computer alone while performing the benchmark, but watch the CPU-Z window and temperature monitor to see how speeds, voltage, and temperature change under load. After the benchmarking is complete, the results can be viewed in a web browser. Geekbench provides both single and multi-core results that should be noted for comparison with subsequent tests. During the test, I noticed a CPU peak temperature of 54 C.

Restart the computer and re-enter UEFI BIOS. As we know the CPU can handle 4.2 GHz (the default turbo speed), on my first overclock attempt I will adjust the core factor limit to 44 which is aimed at a maximum speed of 4.4 GHz. I have not manually adjusted the voltage at this point, but I can do so if these settings are unstable.

Restart your computer and re-open CPU-Z to check core speed and voltage. Thanks to the new settings, we can verify the core speed of 4.4 GHz and the voltage of 1.44 V.

Repeat the benchmark to see if your computer remains stable with a loaded CPU. This time, I noticed the CPU temperature jumped to 71 C, with noticeably more noise being generated by the pump and CPU cooler fans. However, the computer remained stable.

Faster doesn’t always lead to better performance

I achieved overclock to 4.8 GHz before my PC became unstable. At 4.9GHz it was just getting stuck on Windows startup. At this speed, the peak temperature of the hottest core under load reached 87 ° C, which is a bit inconvenient. I’d be tempted to pick a number for security, but the results show what’s possible – at least for this processor.

One final tip: higher CPU speeds do not always lead to better performance. The extra heat generated by overclocking can sometimes cause the CPU to slow down, reducing performance. Take a look at my test results to see the proof:

You can see that after increasing the maximum CPU speed, the single-core test result continuously improves. However, the multi-core test result is more chaotic, peaking at 4.5 GHz and then decreasing with increasing target speed (and peak temperatures). You can find the perfect place – the best balance between speed, warmth and performance. This is another great reason to test CPU performance in small increments. Benchmark and then reinforcement.

Remember that your results may be different from mine with this silicone lottery. But, armed with the basics, take your time to adjust your own processor settings and find its best place. For the taking, you can increase your speed by 10 or 15 percent at no extra cost.

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