All About Fix Prime95 Fatal Error Rounding

All About Fix Prime95 Fatal Error Rounding

Prime95 is a popular software used for testing the stability and performance of computer hardware. However, despite its major benefits, some users may encounter a fatal error known as “Rounding” while running the program. This error can cause frustration and confusion, as it may not be easily understood by the average user. This article will delve into the details of Prime95’s fatal error rounding, its potential causes, and how to effectively troubleshoot and fix it. By understanding this error and its resolution, users can ensure a smooth and successful experience with Prime95.

How to Fix Prime95 ‘Fatal Error: Rounding’

Prime95 is a popular software used for stress testing computers and checking for errors in the CPU. It is commonly used by computer enthusiasts and overclockers to ensure the stability of their systems. However, sometimes users may encounter a ‘Fatal Error: Rounding’ while running Prime95. This error can be frustrating and may cause the system to crash. In this article, we will discuss how to fix Prime95 ‘Fatal Error: Rounding’ to help you get your system up and running smoothly again.

Possible Causes of Prime95 ‘Fatal Error: Rounding’

Before we dive into the solutions, it’s important to understand the possible causes of this error. The ‘Fatal Error: Rounding’ message indicates that Prime95 has encountered a mathematical error (rounding error) during the test. This can be caused by various reasons, such as:

1. Overclocking: If you have overclocked your CPU, it may not be stable enough to handle the stress test and may cause rounding errors.

2. Insufficient cooling: Overheating is one of the most common causes of hardware errors. If your system does not have adequate cooling, it can lead to a rounding error.

3. Faulty hardware: Other hardware components such as RAM, power supply, or motherboard can also cause the ‘Fatal Error: Rounding’.

How to Fix Prime95 ‘Fatal Error: Rounding’

1. Lower the CPU clock speed

As mentioned earlier, overclocking can cause rounding errors in Prime95. If you have overclocked your CPU, try lowering the clock speed. This can help reduce the stress on the CPU and prevent rounding errors. You can also try increasing the CPU voltage to stabilize the system.

2. Check your system’s cooling

If your system is not adequately cooled, it can result in overheating and cause rounding errors. Make sure your CPU is not running too hot while running Prime95. You can use monitoring software like HWMonitor to check the temperature. If the temperature is too high, clean out the dust from your system and ensure that all the fans are working properly.

3. Test your hardware

If the error persists, it’s recommended to test your hardware for any faults. Start by checking your RAM using a memory testing tool like Memtest86. If any errors are found, you may need to replace your RAM. You can also try replacing other hardware components, such as the power supply or motherboard, to see if it resolves the issue.

4. Update your drivers and BIOS

Outdated drivers and BIOS can also cause errors in Prime95. Make sure you have the latest drivers and BIOS version installed on your system. You can check for updates on the manufacturer’s website.

5. Change Prime95 settings

If none of the above solutions work, you can try changing some settings in Prime95. Open the software and go to the ‘Options’ menu. Enable the ‘Round off errors’ option and change the ‘Result file length’ to shorter lengths, such as 4 or 8 bytes. This can help reduce the stress on the CPU and prevent rounding errors.


Prime95 is a useful tool for stress testing your computer, but it can also indicate potential errors in your system. If you encounter the ‘Fatal Error: Rounding’ while running Prime95, try the solutions mentioned above. If the error persists, it’s recommended to seek help from a professional or contact the software’s support team. It’s important to address this issue as

Method 1: Raising the CPU Voltage

One way to improve the performance of your computer’s CPU is by raising the CPU voltage. This can be done by adjusting the processor’s voltage settings in the BIOS or through specialized overclocking software.

Before attempting to increase the CPU voltage, it is important to understand the risks involved. Raising the voltage too high can damage the processor or other components in your computer. It is also important to note that increasing the voltage will generate more heat, so proper cooling is essential.

Here are the steps to follow for raising the CPU voltage:

1. First, determine the safe voltage range for your specific processor. This information can be found on the manufacturer’s website or by doing some research online. Each processor has a maximum safe voltage, and going beyond that threshold can cause damage.

2. Once you know the safe voltage range, enter the BIOS by pressing a specific key (usually F1, F2, or Delete) during startup. The specific key may vary depending on your computer’s manufacturer, so check your user manual if needed.

3. In the BIOS, navigate to the CPU settings or overclocking section. This may be under a different name depending on your motherboard. Look for options related to voltage, such as “CPU Voltage,” “VCore,” or “CPU Overvoltage.”

4. Adjust the voltage by small increments, such as 0.05V, and then save and exit the BIOS. Restart your computer and run a stress test to see if the increased voltage improves performance without causing any issues.

5. If the computer runs stable after the increase, you can continue to raise the voltage in small increments until you reach the desired performance or reach the safe voltage limit.

6. If the stress test fails or your computer experiences stability issues, lower the voltage back to the previous setting and try a smaller increment.

7. Keep a close eye on your computer’s temperature while increasing the voltage. If the temperature gets too high, you may need to invest in additional cooling solutions to keep your system running safely.

It is essential to note that not all processors can handle higher voltages, and not all processors will see a significant performance increase from higher voltages. It is best to research your specific processor and its capabilities before attempting to raise the voltage.

In conclusion, raising the CPU voltage can be an effective way to improve your computer’s performance. However, it should be done carefully and with proper knowledge to avoid damaging your system. Know the safe voltage range for your processor, monitor the temperature closely, and incrementally increase the voltage for the best results. As always, proceed at your own risk and remember to make backups of your important files before making any changes to your system.

Method 2: Clearing the CMOS Battery

Method 2: Clearing the CMOS Battery

If you’ve been dealing with issues on your computer such as boot failure or strange errors, it’s possible that the problem may be caused by a faulty or corrupted BIOS. The BIOS (Basic Input/Output System) is responsible for controlling the basic functions of your computer, and if it becomes corrupted, it can cause a number of issues. One way to fix this is by clearing the CMOS battery.

But first, let’s understand what CMOS is. CMOS stands for Complementary Metal-Oxide-Semiconductor, and it is a small battery-powered chip that stores the BIOS configuration of your computer. This includes information such as the date and time, hardware settings, and boot order. If there is a problem with the CMOS, it can cause issues with the BIOS and affect the overall performance of your computer.

Clearing the CMOS battery is a relatively simple process, but it will require you to open up your computer. Before proceeding, make sure to shut down your computer and unplug it from the power source. You will also need a small flathead screwdriver and a pair of tweezers.

Start by locating the CMOS battery on your motherboard. It is a round, silver battery that is usually attached to the motherboard by a clip. Gently remove the battery using a pair of tweezers, being careful not to damage any other components.

Next, press and hold the power button on your computer for about 10-15 seconds. This will discharge any remaining power in the system and reset the BIOS. After that, wait for a few minutes before placing the CMOS battery back in its slot. Make sure it is inserted correctly, and the clip is securely holding it in place.

Now, put the cover back on your computer and plug it back in. Turn on your computer and check if the issues are resolved. If not, you may need to reset the BIOS settings manually. To do this, enter the BIOS menu by pressing the designated key (usually F2 or DEL) during the boot process. Look for the option to reset to default settings and save the changes before exiting.

In some cases, the CMOS battery itself may be the issue. If the issue persist, try replacing the battery with a new one. CMOS batteries are relatively inexpensive and can be found at most computer hardware stores.

Clearing the CMOS battery is a quick and effective way to fix a variety of BIOS-related issues on your computer. However, if the problem persists, it may be a sign of a more serious issue. In that case, it’s best to consult a professional tech support service.

Method 3: Upgrading the Cooling System (if necessary)

If you have noticed your computer running hotter than usual or experiencing overheating issues, it may be time to upgrade your cooling system. This is especially important for power users who run multiple programs simultaneously or play graphics-intensive games.

Here are some steps you can take to upgrade your computer’s cooling system:

1. Clean Out the Dust
Before making any upgrades, it’s important to clean out any built-up dust and debris in your computer’s cooling system. Use compressed air to blow out dust from the fans and vents. This will ensure that your new cooling system is working at its best.

2. Check Your Current Cooling System
It’s important to know what type of cooling system your computer currently has. This can help you determine what upgrades are necessary for better performance. You can open up your computer’s side panel to check if you have an air cooler or a liquid cooler.

3. Upgrade to an Air Cooler
If your computer currently has an air cooler, you can upgrade to a larger or more efficient one to improve cooling performance. Air coolers come in different sizes and have different heat dissipation capabilities. Check the manufacturer’s specifications to find one that is compatible with your computer and offers better cooling than your current one.

4. Consider a Liquid Cooling System
Liquid cooling systems are more efficient than air coolers as they use a liquid coolant to transfer heat away from the CPU. They are also more expensive and require more maintenance. However, if you are a power user or overclock your CPU, a liquid cooling system can provide better cooling and performance.

5. Install Additional Case Fans
Another option to improve cooling is to add more case fans. These fans help to circulate air inside the computer case, keeping components cool. If you have empty fan slots in your case, you can install additional case fans to improve air flow and cooling.

6. Upgrade Your PC Case
In some cases, the issue may not be with the cooling system itself, but rather the case design. If your case does not have sufficient air flow or lacks space for additional fans, it may be time to upgrade to a more spacious and well-ventilated case. This will allow for better air circulation and cooling.

7. Monitor System Temperatures
After upgrading your cooling system, it’s important to monitor system temperatures to ensure that they are within safe levels. You can use software such as SpeedFan or HWMonitor to track your computer’s temperature and adjust settings if needed.

In conclusion, upgrading your computer’s cooling system can significantly improve its performance and prevent overheating. Regularly cleaning out dust and debris and keeping an eye on system temperatures can also help maintain good cooling performance. With these tips, you can ensure that your computer stays cool and runs smoothly for years to come.

Method 4: Upgrade PSU or Lower the Overclocked Frequencies

As technology advances and new components are released, it is becoming increasingly popular for people to overclock their systems for better performance. While overclocking can provide a noticeable boost in speed, it can also put a strain on your power supply unit (PSU). This can lead to system crashes, instability, and in extreme cases, even hardware damage. In this article, we will discuss the importance of having a sufficient PSU and how to upgrade it or lower the overclocked frequencies to prevent any potential issues.

Why a Sufficient PSU is Important for Overclocking

An overclocked system requires more power to run compared to a non-overclocked one. This is because the CPU, GPU, and other components are running at higher frequencies and voltages, thus drawing more power from the PSU. If your PSU is not able to deliver the required amount of power, it can lead to instability and crashes. Moreover, an insufficient PSU can also cause damage to your hardware in the long run.

How to Determine if You Need to Upgrade Your PSU

The first step is to determine the power consumption of your system. There are various online PSU calculators available that can help you estimate the power consumption of your system based on the components you have. Once you have the estimated power consumption, add at least 20% to it as a buffer to account for any spikes in power demand. This will give you the minimum wattage your PSU should have. Compare this number to the wattage of your current PSU. If your current PSU falls short, it is time for an upgrade.

Upgrading Your PSU

When upgrading your PSU, there are a few things to consider. First, make sure to choose a reputable brand and a high-quality unit. A cheap, low-quality PSU can cause just as many issues as an insufficient one. Next, make sure that the wattage of the new PSU is sufficient for your system’s needs, as calculated earlier. Lastly, consider future upgrades and choose a PSU with a bit more wattage than what you need to accommodate any potential upgrades.

Lowering the Overclocked Frequencies

Alternatively, if you do not want to upgrade your PSU, you can lower the overclocked frequencies to decrease the power demand. This will ensure that your current PSU can handle the load without any issues. Most overclocking utilities have a voltage or power limit setting that you can adjust to reduce the power consumption. You can also try lowering the frequencies gradually until you find a balance between performance and stability.

Final Thoughts

Having a sufficient PSU is crucial for a stable and reliable system, especially when overclocking. Before undertaking any overclocking activities, it is essential to ensure that your PSU can handle the load. If your current PSU falls short, consider upgrading to a higher wattage unit. Alternatively, you can also lower the overclocked frequencies to decrease the power demand. By following these steps, you can ensure that your system runs smoothly and your hardware stays safe while overclocking.


In conclusion, Prime95 is a popular stress testing tool for computer hardware and can be extremely useful in ensuring stability and performance. However, it is not uncommon to encounter fatal error rounding during its use, which can be frustrating and confusing for users. By understanding the causes of this error and implementing the recommended solutions, such as adjusting hardware settings and updating drivers, users can successfully resolve the issue and continue to use Prime95 effectively. It is also important to regularly monitor for any hardware issues and perform routine maintenance to prevent future fatal error rounding. With the proper precautions and knowledge, Prime95 can continue to be a valuable tool for stress testing and optimizing computer performance.

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