Best PC Hardware Diagnostic Software
Sometimes a PC suddenly crashes for no obvious reason, restarts on its own, overheats unexpectedly, or becomes frustratingly slow. Before you consider reinstalling Windows or replacing your computer altogether, it’s important to first check whether one of the hardware components is close to failing.
Fortunately, there are many reliable free hardware diagnostic tools that can help you analyze your system and detect potential issues, whether they’re caused by high temperatures, a failing hard drive, faulty RAM, or an unstable power supply. These tools are designed to catch problems early and rarely miss critical hardware warnings.
In this article, we’ll highlight the best PC hardware diagnostic software that can help you identify most hardware-related issues on your computer, even if you’re not an expert in PC maintenance or repair.
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| Best PC Hardware Diagnostic Software |
PC Software to Detect Hardware Problems
To determine whether your computer is suffering from a hardware-related issue, we recommend the following selection of free diagnostic software capable of identifying most common faults affecting core system components. This list has been carefully curated and is sufficient to diagnose nearly 90% of hardware stability issues and failures encountered by everyday users.
If you’re looking for a more advanced or in-depth analysis, you’ll also find additional specialized tools at the end of this article designed for deeper hardware inspection and troubleshooting.
HWMonitor
A computer that runs at abnormally high temperatures often suffers from performance slowdowns, unexpected app crashes, or even sudden shutdowns. To accurately monitor component temperatures and determine whether any part has exceeded safe limits, HWMonitor is one of the best tools available. It’s a lightweight, free utility that displays real-time temperature readings and other hardware data in a clear, easy-to-understand interface.
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| HWMonitor |
With HWMonitor, you can closely monitor your CPU temperature, which is typically the hottest component in any PC. When CPU temperatures rise too high, the system may slow down significantly or automatically shut down to protect the hardware. Under normal conditions, an idle CPU temperature between 35°C and 50°C (95°F–122°F) is perfectly safe. During heavy workloads, such as gaming or video editing, temperatures between 60°C and 80°C (140°F–176°F) are still considered acceptable.
However, if CPU temperatures frequently exceed 85°C (185°F), you should start monitoring the situation more carefully. Repeated exposure to this range may require cleaning the cooling fan, replacing the thermal paste, or upgrading the cooling solution. If temperatures reach 95°C (203°F) or higher, the CPU is entering a critical zone. At this point, it may throttle its performance or cause unexpected restarts, which can negatively affect long-term hardware lifespan and system stability.
The same principles apply to the graphics card (GPU). It’s normal for GPU temperatures to rise when running games or 3D applications, but every graphics card has its own safe operating limits.
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| HWMonitor - SSD temperatures |
When it comes to storage temperatures, SSDs (especially NVMe M.2 drives) tend to generate more heat compared to traditional HDDs. While modern SSDs are designed to withstand higher temperatures, excessive heat can still reduce performance and shorten their lifespan. Ideally, SSD temperatures should remain between 30°C and 45°C (86°F–113°F). Temperatures in the 50°C–60°C (122°F–140°F) range are acceptable, particularly if the drive lacks a dedicated heatsink. However, if temperatures climb to 70°C–80°C (158°F–176°F) or higher, you may experience thermal throttling, leading to slower speeds or write errors.
HWMonitor also displays power supply voltage readings (3.3V, 5V, and 12V rails) along with fan speeds. If these voltages are unstable or significantly below normal levels, it could indicate a failing power supply. Likewise, if a fan is not spinning or constantly running at 100%, it may point to cooling or airflow issues that need immediate attention.
OCCT
If your computer restarts randomly, crashes without warning, or freezes as soon as you launch demanding applications, it may be time to test its overall stability. OCCT is one of the most comprehensive tools available for this purpose. This free utility allows you to perform stress tests on key components such as the CPU, GPU, RAM, and power supply, helping you determine whether your system can handle heavy workloads or fails under pressure. Stress testing is one of the most reliable ways to reproduce hardware-related issues and pinpoint the exact component causing the problem.
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| OCCT |
In the program’s sidebar, you’ll find multiple testing modules, each designed for a specific component. The CPU + RAM test stresses both the processor and memory simultaneously, making it useful for evaluating how well they perform together under load. The CPU test focuses solely on the processor and offers detailed configuration options, including stress level, instruction sets, and the number of threads used.
There’s also LINPACK, an extremely intensive CPU stress test commonly used to verify processor stability after overclocking. However, it’s not recommended if your goal is simply to check temperatures, as it generates unusually high thermal loads.
For memory testing, the MEMORY section allows you to test RAM independently, similar to tools like MemTest64, but conveniently built directly into OCCT. GPU testing is handled through 3D ADAPTIVE and VRAM, which evaluate graphics card performance using demanding 3D scenes and video memory checks.
The POWER test pushes both the CPU and GPU at the same time, making it especially useful for assessing power supply stability and determining whether your PSU can meet the system’s energy demands under full load. Meanwhile, the COMBINED mode lets you run multiple tests in a single session, providing a more complete and holistic system stress test.
During any OCCT test, it’s essential to closely monitor temperatures, voltage levels, CPU/GPU usage, estimated power consumption, and memory errors (if any occur). OCCT presents this data using clear, real-time graphs, making it easier to detect overheating, sudden voltage drops, or abnormal performance behavior.
Important Warning: OCCT stress tests are designed to push your hardware to its absolute limits. If you notice temperatures rising too quickly or exceeding safe thresholds, it’s strongly recommended to stop the test manually immediately. OCCT does not automatically halt tests when critical temperatures are reached, so active monitoring throughout the entire testing process is crucial to prevent potential hardware damage. {alertWarning}
CrystalDiskInfo
If your computer takes noticeably longer to boot into Windows, file loading has become slower than usual, or some files suddenly become inaccessible, your storage drive may be starting to fail. To check the health of your drive, CrystalDiskInfo is one of the best tools you can use. It’s a free, lightweight utility that reads S.M.A.R.T. data from your storage device, allowing you to determine whether your drive is still healthy or if it’s time to back up your data before it’s too late.
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| CrystalDiskInfo |
CrystalDiskInfo features a simple and easy-to-understand interface, even for beginners. It uses a clear color-coded system to display drive health status:
- Blue indicates the drive is working normally and is in good condition.
- Yellow means some warning indicators have appeared and the drive should be monitored closely.
- Red signals serious problems, meaning you should urgently back up your data and replace the drive as soon as possible.
Beyond the overall health status, the program provides valuable technical information such as drive temperature, total power-on hours, startup and shutdown counts, and detailed data related to read errors, reallocated sectors, and other critical metrics. At the bottom, you’ll also find a full list of S.M.A.R.T. attributes. While there are many values, the most important ones to focus on include:
- Available Spare: If this value starts decreasing, it means the SSD is consuming its reserved spare memory blocks.
- Available Spare Threshold: Indicates the minimum spare level at which the drive will officially report a critical condition.
- Percentage Used: Represents the estimated overall wear level of the SSD. When it reaches 100%, the drive is considered to have reached its theoretical end of life.
- Media and Data Integrity Errors: Any value here indicates that read or write errors have occurred on the drive.
- Unsafe Shutdowns: Shows how many times the drive was powered off improperly, such as during power outages or sudden system crashes.
Overall, CrystalDiskInfo is an essential tool for early detection of storage issues, helping you avoid unexpected data loss and make informed decisions before a drive fails completely.
UserDiag
If you’re looking for a tool that gives you a complete overview of your PC’s health, UserDiag does an excellent job. It’s a completely free program designed for users who want a clear and easy-to-understand diagnosis without relying on multiple tools. In just a few minutes, UserDiag scans your core hardware components, measures performance, monitors temperatures, and then presents the results in a clean, well-organized visual report that shows everything you need to know about your system.
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| UserDiag |
When you launch the program, you can choose the type of scan that best suits your needs:
- Quick Diagnosis (about 5 minutes): Ideal for a fast initial check. It provides an overview of your PC’s general condition and detects common issues.
- Long Diagnosis (around 20 minutes): Similar to the quick scan but more detailed, making it suitable for identifying problems that appear after extended use.
- Extreme Diagnosis (about 20 minutes): Pushes your system to its maximum limits, similar to stress-testing tools like OCCT. Temperatures rise significantly during this test, and it does not represent normal daily usage. It’s best reserved for special cases only.
If you’re unsure which option to choose, it’s recommended to start with the Quick Diagnosis.
Once the test is complete, UserDiag displays a results page divided into multiple sections. It clearly indicates whether any issues were detected and, if so, provides suggested solutions with detailed explanations. The report also includes average and maximum CPU temperatures, clock speeds, core count, as well as detailed information about your GPU, RAM, and storage drives. In addition, it shows display resolution, refresh rate, Windows version details, and more.
All this information is presented in a color-coded, structured layout, making it easy to understand even for users with little to no technical experience. Overall, UserDiag is a great choice for anyone who wants a simple yet comprehensive PC hardware diagnostic tool without complexity.
Other Useful Tools You May Need in Specific Cases
The four programs we covered earlier already handle the core hardware diagnostic needs for most users. However, if you want a deeper level of analysis, or if the issue persists despite using those tools, the following additional utilities are worth keeping on hand for special situations.
MemTest86
While tools like OCCT and UserDiag can detect memory-related issues, MemTest86 remains the gold standard for RAM testing. It must be run from a bootable USB drive, not from within Windows, which allows it to detect memory errors that the operating system itself may fail to identify. This makes it especially useful for diagnosing random crashes, freezes, or system instability caused by faulty RAM.
BlueScreenView
If your PC frequently crashes and displays the infamous Blue Screen of Death (BSOD), this lightweight tool can help you pinpoint the cause. BlueScreenView reads Windows crash dump files and highlights the driver or system file responsible for the crash. This makes it easier to determine whether the issue is hardware-related or caused by software problems, such as a faulty driver or a bad Windows update.
CPU-Z
CPU-Z is commonly used to display detailed information about your system components, including the CPU, motherboard, and RAM. It shows clock speeds, core count, voltages, and memory timings in real time. The program also includes a built-in benchmark tool that lets you compare your processor’s performance against similar CPUs, making it useful for verifying whether your CPU is running at its expected performance level.
GPU-Z
For users who want more in-depth information about their graphics card, GPU-Z provides highly detailed data such as GPU clock speeds, temperature, usage percentage, power consumption, and VRAM usage. It’s an excellent companion to tools like HWMonitor or OCCT when diagnosing GPU-related performance or stability issues.
Conclusion
Diagnosing hardware issues doesn’t have to be intimidating, even if you’re not a tech expert. With the right tools, you can monitor temperatures, test stability, and detect failing components before they lead to major problems or data loss. Programs like HWMonitor, OCCT, CrystalDiskInfo, and UserDiag cover most everyday needs, while specialized tools such as MemTest86, BlueScreenView, CPU-Z, and GPU-Z provide deeper insights for more complex cases. By regularly checking your PC with these utilities, you can maintain peak performance, extend hardware lifespan, and avoid unexpected crashes, all without costly repairs or guesswork.
Keeping these tools handy ensures that your computer stays reliable, whether for work, gaming, or creative projects.