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How to Find Out What Power Supply You Have Without Opening Computer?

With rapidly evolving technological landscape, understanding the components that power our digital devices is essential for smooth and reliable performance. Among these components, the power supply unit (PSU) stands as a critical backbone, ensuring a steady and efficient flow of electrical power to every internal component within a computer system. Knowing the wattage and specifications of your power supply is paramount, as it determines the system’s stability, performance, and ability to accommodate future hardware upgrades.

Traditionally, obtaining power supply information required physically opening the computer case or consulting technical manuals. However, with advancements in software tools, online resources, and external devices, users now have various non-invasive methods at their disposal to check the power supply wattage without the need to access the hardware directly.

In this comprehensive guide, we will explore different methods for determining the power supply wattage without opening the computer. Each method offers its unique advantages and limitations, catering to users of all technical backgrounds and preferences.

Importance of Knowing Power Supply Wattage

The power supply unit (PSU) is a crucial component of any computer system, as it is responsible for providing a steady and reliable flow of electrical power to all the internal components. Understanding the wattage of your power supply is essential for several reasons.

Component Compatibility

Different computer components, such as the CPU, GPU, and other peripherals, have specific power requirements. Knowing the wattage of your power supply ensures that it can adequately handle the power demands of all the components in your system. Using an insufficient power supply can lead to performance issues, system instability, and even potential damage to the hardware.

Upgrading Components

If you plan to upgrade your computer’s hardware, especially power-hungry components like high-end graphics cards or processors, you need to be aware of your power supply’s capacity. Upgrading without considering the power supply can lead to system failures or the need for an additional PSU upgrade.

Overloading Prevention

Running a power supply beyond its maximum wattage capacity can result in overheating and may trigger overcurrent protection, causing sudden shutdowns and data loss. Knowing your power supply’s wattage prevents you from overloading it and maintains the stability of your system.

Efficiency and Electricity Cost

Power supplies have different levels of efficiency at various load levels. By knowing the wattage, you can estimate your system’s power consumption and its impact on your electricity bill. A higher efficiency PSU can help save energy and reduce long-term operational costs.

How to Find Out What Power Supply You Have Without Opening Computer?

Using Software Tools

Modern software tools have made it easier than ever to gather information about computer hardware, including the power supply wattage, without the need to physically access the components. These software tools are specifically designed to interact with the computer’s hardware and provide detailed system information. Some of the most common software tools for power supply detection include:

  • CPU-Z: CPU-Z is a popular and widely-used utility that provides comprehensive information about the CPU, motherboard, memory, and power supply. It can display the power supply’s wattage and other relevant specifications.
  • HWiNFO: HWiNFO is a powerful system information and diagnostic tool that offers in-depth details about various hardware components, including the power supply. It can detect and report the wattage and other essential parameters.
  • Speccy: Speccy is a user-friendly software tool that presents a detailed overview of the computer’s hardware configuration, including the power supply specifications.
  • AIDA64: AIDA64 is an all-in-one system information and benchmarking tool that provides comprehensive hardware information, including power supply details.
  • Open Hardware Monitor: This open-source software tool allows users to monitor various hardware sensors and provides power supply information, including wattage, voltage, and temperature.

Step-by-Step Guide to Using Software Tools

To check the power supply wattage using software tools, follow these general steps.

  • Visit the official website of the software tool you prefer and download the latest version compatible with your operating system. Install the software by following the on-screen instructions.
  • Once installed, open the software tool from the Start menu or desktop shortcut.
  • Depending on the software tool, the navigation might differ slightly, but generally, you should find a section labeled “Power Supply” or “PSU” within the software’s interface.
  • In the “Power Supply” section, you should see the wattage of your power supply listed, along with other relevant information such as voltage levels and power efficiency.
  • Some software tools may provide additional information, such as the power supply’s model, manufacturer, and serial number.

Pros and Cons


  • Software tools offer a user-friendly interface, making them accessible to users with varying levels of technical expertise.
  • This method does not require physically opening the computer, reducing the risk of accidental damage to hardware components.
  • Checking the power supply wattage with software tools is a fast and convenient process that can be completed within a few minutes.
  • Software tools provide not only the power supply wattage but also other relevant details, allowing users to have a comprehensive understanding of their system.


  • The accuracy of power supply detection through software tools may vary. In some cases, the software might not be able to detect the power supply’s wattage accurately, especially if the power supply model is not well-known or if there are compatibility issues.
  • Some software tools may not be fully compatible with certain operating systems or hardware configurations, limiting their effectiveness for some users.
  • Users relying solely on software tools may face limitations if they need to gather system information on a computer with a malfunctioning OS or if they don’t have access to the specific software tool at a given time.

Using software tools to check the power supply wattage offers an accessible and convenient method for users to obtain crucial information about their computer system. While it generally provides detailed and accurate data, users should be aware of potential compatibility issues and consider alternative methods if the software fails to retrieve accurate information.

Manufacturer’s Website

The manufacturer’s website is an excellent resource for obtaining accurate and detailed information about your computer’s components, including the power supply. Most reputable computer manufacturers provide comprehensive product specifications and documentation on their websites. Here’s how to find power supply information on the manufacturer’s website.

  • Determine the brand and model of your computer or motherboard. This information is usually displayed on the computer case or can be found in the system information of your operating system.
  • Go to the official website of the manufacturer. You can typically find it by performing a quick internet search using the manufacturer’s name.
  • Look for a “Support” or “Products” section on the manufacturer’s website. In many cases, you can access this section from the homepage or the main navigation menu.
  • On the support or product page, you may be prompted to enter your computer’s model number or select the specific product line that matches your device.
  • Once you’ve located your specific computer or motherboard model, browse through the available resources. Look for sections like “Specifications,” “Technical Specifications,” or “Manuals.”
  • Within the specifications or manuals, search for details related to the power supply. This information should include the wattage, voltage, amperage, and other relevant specifications.

How to Locate the Required Details?

Follow these steps to locate the power supply information on the manufacturer’s website.

  • Manufacturers often provide a detailed list of technical specifications for each of their products. Check for a section labeled “Technical Specifications” or something similar.
  • If the manufacturer offers a wide range of products, you may need to filter the search results by product type (e.g., desktop computers, motherboards) to find the specific model that matches your system.
  • If available, download the product manual for your computer or motherboard. The manual should contain all the necessary information about the power supply, including its wattage and other relevant specifications.
  • Some manufacturers have separate product pages for each model. These pages often include detailed specifications, including the power supply details.

Limitations of this Method

While using the manufacturer’s website to find power supply information is generally reliable and straightforward, there are some considerations and limitations to be aware of.

  • Manufacturers may update their product lineup over time, and older models might not be listed on their websites. If you have an older computer or motherboard, finding detailed information may be more challenging.
  • Manufacturers may offer different configurations for the same model, especially for desktop computers. The power supply wattage might vary depending on the chosen configuration, so ensure you are looking at the correct specifications for your specific model.
  • If you have a custom-built computer with components from different manufacturers, you might not find all the details, including the power supply wattage, on the manufacturer’s website. In such cases, you may need to rely on other methods, such as software tools or external devices.
  • Manufacturer websites may be available in multiple languages, and navigation can differ based on regional variations. Ensure you are on the correct website and select the appropriate language, if necessary, to find the relevant information.
  • If you have trouble locating the power supply information on the website, consider reaching out to the manufacturer’s customer support for assistance. They can guide you to the right resources or provide the required details directly.

Using the manufacturer’s website to find power supply information is a reliable method that can provide accurate and detailed specifications for your computer’s components. However, be mindful of model availability, variability, and potential language or navigation challenges. If the required information is not readily available, consider contacting the manufacturer’s support team for further assistance.

Utilizing System Information

Windows operating systems provide a built-in tool called “System Information” that offers a comprehensive overview of the computer’s hardware and software configuration. To access the System Information tool on Windows:

  • Press the Windows key + R on your keyboard. This will open the “Run” dialog box.
  • Type “msinfo32” (without quotes) in the Run dialog box and press Enter or click OK.
  • The System Information window will open, displaying various categories of information about your computer.

Identifying Power Supply Specifications

In the System Information window, you can find the power supply specifications as follows:

  • Look for “System Summary” in the left pane and click on it. This will display general information about your computer on the right side.
  • Scroll down in the right pane and find the entry labeled “BIOS Version/Date.”
  • Next to “BIOS Version/Date,” there is an entry called “SMBIOS Version.” This value represents the version of the System Management BIOS (SMBIOS) specification.
  • Note down the SMBIOS version. It will be something like “2.4” or “3.0.”
  • Once you have the SMBIOS version, search for the corresponding SMBIOS version and power supply information on websites that provide hardware database information. These websites often have detailed information on various computer models, including the power supply wattage.
  • Additionally, some computers may display the power supply wattage directly in the System Information window under the “BIOS Version/Date” field. Look for entries like “Power Supply” or “PSU Wattage.”

Similar Procedures for macOS and Linux


  • Click on the Apple logo in the top-left corner of the screen.
  • Select “About This Mac” from the drop-down menu.
  • In the “Overview” tab, you will find basic information about your Mac, including the model name.
  • To obtain detailed hardware information, click on “System Report.”
  • In the “Hardware” section, navigate to “Power” to find information about the power supply, including its wattage.


  • Open a terminal window by pressing Ctrl + Alt + T or searching for “Terminal” in the applications.
  • Use system information commands such as “lshw” or “inxi” to gather detailed hardware information about your computer, including the power supply specifications.
  • For example, running the command “sudo lshw -class power” or “inxi -P” may provide power supply-related details.
  • It is important to note that while the System Information tool and other commands can provide valuable information about the power supply, some computer models or custom-built systems may not display this information. In such cases, alternative methods like using software tools or contacting the manufacturer’s support might be necessary to obtain accurate power supply specifications.

Exploring the Motherboard Manual

The motherboard manual is a comprehensive guide provided by the motherboard manufacturer. It contains detailed information about the motherboard’s features, specifications, installation instructions, and hardware compatibility. To access the motherboard manual:

  • Locate the model name or number of your motherboard. This information is usually printed directly on the motherboard itself or can be found on the motherboard’s original packaging.
  • Go to the official website of the motherboard manufacturer. Look for a “Support” or “Downloads” section on the manufacturer’s website. This section typically contains resources like manuals and drivers.
  • Enter the motherboard’s model name or number in the search or product support section to find the appropriate manual.
  • Once you’ve found the correct manual for your motherboard model, download it in PDF format for easy reference.

Finding Power Supply Details in the Documentation

After accessing the motherboard manual, follow these steps to find power supply details:

  • Start by checking the table of contents or index of the motherboard manual. Look for sections related to “Specifications,” “Hardware Specifications,” or “Component Descriptions.”
  • Within the appropriate section, there should be specific details about the power supply. This information might include the supported power supply wattage, voltage requirements, and connector types.
  • Look for a diagram or description of the motherboard’s power connectors. This section should indicate the types of power connectors required for the motherboard, such as the main 24-pin ATX connector and the CPU power connector (usually 4 or 8 pins).
  • Some motherboard manuals may provide additional information about power delivery technologies, such as power phase designs, voltage regulation modules (VRMs), and power protection features.
  • In some cases, the motherboard manual may also provide recommendations or guidelines for selecting an appropriate power supply based on the system’s configuration.

Compatibility Considerations

  • When consulting the motherboard documentation for power supply information, it is essential to consider the following compatibility aspects:
  • Ensure that the power supply’s wattage is sufficient to meet the power demands of all the components in your system, including the motherboard, CPU, GPU, and other peripherals. It is recommended to have a power supply with a slightly higher wattage than the total power consumption of all components to allow for future upgrades and system stability.
  • Verify that the power supply you are considering has the necessary connectors to fit your motherboard’s power requirements. Common connectors include the 24-pin ATX main connector, the CPU power connector (4 or 8 pins), and various PCIe connectors for graphics cards.
  • Consider choosing a power supply with a high efficiency rating (80 PLUS Bronze, Silver, Gold, Platinum, or Titanium) to minimize energy wastage and reduce operating costs. Additionally, look for power supplies with safety certifications like UL, CE, or FCC for reliable and safe operation.
  • Modular power supplies allow you to detach unused cables, leading to a cleaner and more organized system build. Non-modular power supplies have fixed cables, which may result in cable clutter if not managed properly.

By carefully reviewing the motherboard documentation and ensuring compatibility with the power supply, you can make an informed decision that will lead to a stable and efficient computer system. If you have any doubts or questions about the power supply compatibility, consider seeking advice from computer hardware experts or the manufacturer’s customer support team.

Using External Devices

External power supply testers are handy tools designed to check the functionality and specifications of a power supply unit without the need to connect it to a computer or open the computer case. These devices provide a non-invasive and standalone method of testing the power supply, ensuring that it is in proper working condition. They are particularly useful for users who want to verify the health of their power supply before or after installation, during troubleshooting, or when dealing with suspected power-related issues.

External power supply testers typically come with an LCD or LED display that shows essential information about the power supply, such as voltage outputs, wattage, and fan speed. Some testers also include audible alarms to alert users about potential issues, such as overvoltage or undervoltage conditions.

Step-by-Step Guide to Testing Without Opening the Computer

To use an external power supply tester without opening the computer, follow these steps:

  • Before starting the testing process, make sure the power supply is not connected to any power source and is completely unplugged from the wall outlet or power strip.
  • Plug one end of the external power supply tester into the 24-pin ATX main connector of the power supply. Some testers may also include additional connectors for CPUs and PCIe connectors if you want to test those as well.
  • Once the tester is connected to the power supply, turn on the power supply using the switch (if available) or by plugging it into a power source.
  • The external power supply tester’s display will show information about the voltage outputs on various rails (e.g., +12V, +5V, +3.3V) and the total wattage being supplied by the power supply.
  • If the power supply is functioning correctly, the tester’s display will show stable voltage readings within acceptable ranges. Any discrepancies or anomalies, such as extremely low or high voltages, may indicate a faulty power supply.
  • Some testers have built-in audible alarms that sound if certain conditions are not met, such as overvoltage, undervoltage, or no power output.
  • Some advanced testers may also include a feature to test the power supply’s fan by ramping up its speed to ensure it’s working correctly.
  • After testing, turn off the power supply and unplug it from the power source. Then, disconnect the tester from the power supply.

Pros and Cons of Using External Devices


  • External power supply testers provide a non-invasive way to check the power supply’s functionality without connecting it to a computer or opening the computer case.
  • Testing with an external device is a relatively quick process and does not require technical knowledge or experience. It allows users to verify the power supply’s health in a matter of minutes.
  • The tester works independently of any computer system, making it useful for testing power supplies outside of the computer or during troubleshooting without interfering with the rest of the components.
  • Using an external tester avoids the potential risk of damaging computer components during testing, as it eliminates the need to interact with the computer’s internals.


External testers primarily focus on testing the voltage outputs and wattage of the power supply. They do not provide information about the overall system’s stability or the power supply’s performance under a load.

While testers can show voltage readings, they do not place a real load on the power supply like a computer system does during normal operation. This means some issues might only be evident when the power supply is under an actual load.

Purchasing an external power supply tester is an additional cost, especially for users who may only need to use it occasionally.

External power supply testers offer a convenient and non-invasive method to test the functionality of a power supply without opening the computer case or connecting it to a computer system. They are particularly useful for quick checks and initial troubleshooting, but they do have limitations when it comes to comprehensive load testing and evaluating the power supply’s performance under real operating conditions.

Contact Manufacturer Support

Contacting the manufacturer’s support team is a viable method to obtain accurate and reliable information about your power supply, especially if you are unable to find the required details through other means. Most reputable computer and power supply manufacturers have dedicated customer support channels, such as email, phone, or live chat, where users can seek assistance with their products. Exploring this option can be particularly helpful if you have a custom-built computer or a power supply with specific configurations.

Before reaching out to the manufacturer support, it is a good idea to gather as much information about your computer or power supply as possible. This includes details such as the brand and model of your computer or motherboard, the power supply model (if known), and any other relevant specifications or labels on the power supply.

Necessary Information to Provide

When contacting the manufacturer’s support team for power supply information, providing the following details will help them assist you more effectively.

  • Clearly state the brand and model of your computer or motherboard. If you have a custom-built computer, mention the motherboard model.
  • If you can identify the power supply model, provide this information. You can find it on a label attached to the power supply.
  • Look for any other labels or markings on the power supply that might contain relevant information, such as wattage, voltage, amperage, or manufacturer part numbers.
  • Clearly specify the information you need about the power supply. For example, if you are interested in the power supply wattage, voltage levels, or specific connectors, communicate this to the support representative.
  • Inform the support team why you need the power supply information. Whether it’s for system upgrades, troubleshooting, or general knowledge, this context can help them provide relevant details.

Response Time and Reliability

The response time and reliability of manufacturer support can vary depending on the brand and the support team’s efficiency. In general, reputable manufacturers strive to provide timely and accurate support to their customers. However, several factors can influence the response time:

Manufacturer support teams typically operate during regular business hours. Be mindful of time zones and any potential holidays that may affect response times. Different support channels may have varying response times. For urgent inquiries, phone or live chat support might offer quicker responses compared to email.

Support teams handle multiple inquiries daily, so response times may vary based on the volume of requests they receive. The complexity of your inquiry may also impact the response time. Straightforward questions may receive quicker replies than more complex technical inquiries.

To ensure a more reliable response, it is a good practice to provide all relevant details and be clear about the specific information you need. If you don’t receive a response within a reasonable timeframe, you can consider trying another support channel or reaching out to the manufacturer’s social media channels, where they may also provide assistance.

Contacting the manufacturer’s support team is a reliable way to obtain accurate power supply information when other methods are not feasible or available. By providing the necessary details and being clear about your inquiry, you can increase the chances of receiving a prompt and helpful response from the manufacturer’s support representatives.


How do I check the power supply wattage without opening my computer?

Answer: You can use software tools, consult the manufacturer’s website or motherboard documentation, use an external power supply tester, or contact the manufacturer’s support for assistance.

Why is knowing the power supply wattage important for my computer?

Answer: Knowing the power supply wattage is crucial for ensuring compatibility with your computer’s components, avoiding system instability, and preventing potential damage due to power overload.

Can I use any power supply with my computer?

Answer: No, you should use a power supply that meets the wattage requirements of your components and has the appropriate connectors for your motherboard and peripherals. Using an inadequate power supply can lead to performance issues and even hardware damage.

Is there a specific software tool to check the power supply wattage?

Answer: Yes, various software tools like CPU-Z, HWiNFO, and Speccy can provide power supply information. However, the accuracy and availability of this information may vary depending on your system and the software used.


understanding the critical components that power our computers is vital for ensuring optimal performance and stability. The power supply unit (PSU) plays a crucial role in delivering reliable electrical power to all internal components, making it essential to know the wattage and specifications of this critical component.

Throughout this comprehensive guide, we have explored six diverse methods for checking the power supply wattage without the need to physically open the computer case. Each method offers unique advantages, catering to users with varying technical expertise and preferences.

Using software tools, we can effortlessly access detailed hardware information, enabling us to quickly retrieve the power supply wattage and other crucial specifications. By consulting the manufacturer’s website and exploring the motherboard documentation, we gain insights directly from the source, ensuring accuracy and compatibility.

For a standalone and non-invasive testing approach, external power supply testers provide a convenient solution, allowing us to verify the health of our power supply without connecting it to a computer system.

In some cases, when all other avenues are exhausted, reaching out to the manufacturer’s support team offers a reliable means of obtaining accurate power supply information. By providing essential details and context, we enhance the chances of receiving prompt and helpful assistance.

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