When the Lights Stay On: Unpacking Unpredictable PC Shutdowns


I’ve assembled a PC approximately two months ago and am encountering an intermittent shutdown issue. The system randomly powers off without warning—this can occur several times a day or may not happen for up to 20 days. During these incidents, all components except the fans and their lights shut down, and the CPU indicator on the motherboard illuminates. To restart the PC, I must toggle the PSU switch off and then on. Despite thorough testing, the CPU does not power off, and temperature readings remain within normal ranges, ruling out overheating as the cause.

Efforts to resolve the issue have included:

  • Running system file checks (`sfc /scannow`) and Windows Memory Diagnostic.
  • Making unspecified adjustments to Windows settings.
  • Modifying BIOS settings, such as power loading, EXPO, XMP, Power Supply idle control, and attempting a BIOS update.
  • Using dual PSU-to-GPU cables.
  • Inspecting for loose connections.
  • Conducting an OCCT power test, which returned no errors.
  • Reinstalling Windows 10, which did not rectify the problem.
  • Given these steps and the specifications listed below, I seek expert guidance on the matter. If the solution might involve replacing the PSU, could you recommend a suitable model?


  • CPU: AMD Ryzen 5 7600X
  • CPU Cooler: Deepcool AG620 WH ARGB
  • Motherboard: Gigabyte B650 GAMING X AX ATX
  • Memory: TEAMGROUP T-Create Expert 32 GB (2 x 16 GB) DDR5-6000 CL30
  • Storage: TEAMGROUP T-Force Cardea Z44Q 2 TB
  • GPU: Sapphire PULSE Radeon RX 7900 XT
  • PSU: Corsair RM850x (2021)
  • Case: Lian Li LANCOOL 216″
  • This

rephrased question is now structured to directly address an expert, highlighting the troubleshooting steps taken and seeking further advice on the issue. Is there anything else you would like to add or modify?


Intermittent PC shutdowns can be a perplexing issue, even for the most seasoned computer enthusiasts. The problem you’re experiencing, where the system powers off without warning and only the fans and their lights remain operational, is indeed a cause for concern. The fact that the CPU indicator on the motherboard lights up suggests that the system is recognizing an issue with the CPU or related components, despite the CPU’s temperature readings being normal.

Your efforts to resolve the issue have been comprehensive, including system file checks, memory diagnostics, BIOS adjustments, and even a full reinstallation of Windows. These steps eliminate many common software-related causes of shutdowns. The use of dual PSU-to-GPU cables and checking for loose connections are also prudent steps in ensuring hardware stability.

Given the troubleshooting steps you’ve already taken, we can consider other potential causes for these shutdowns:

: A faulty PSU can cause intermittent shutdowns. Although you’ve tried two different PSU cables, the PSU itself might be the problem. It’s recommended to test with another PSU if possible. For your system, a PSU like the Seasonic Prime TX-850 or the Thermaltake Toughpower GF3 ATX 3.0 could be suitable replacements, offering high efficiency and stable power delivery.


Motherboard Faults

: A less common, but possible cause could be an issue with the motherboard itself. This could be due to a faulty component or circuit on the board.


Electrical Issues

: Fluctuations in your home’s electrical supply could cause the system to shut down. An Uninterruptible Power Supply (UPS) could help regulate the voltage supplied to your PC.


Overheating Components Other Than the CPU

: While the CPU temperatures are normal, other components, such as the GPU or VRMs (Voltage Regulator Modules), could be overheating. Ensure that all cooling systems are functioning correctly and that there’s adequate airflow in the case.


Driver or Hardware Compatibility

: Ensure that all drivers are up to date, especially for the GPU. Also, check for any known compatibility issues between your hardware components.



: Although less likely given the steps you’ve taken, it’s worth running a thorough malware scan using a reliable antivirus program.


Hardware Stress Tests

: While OCCT didn’t show errors, consider running other stress tests targeting different components, such as the GPU or RAM.


Event Logs

: Check the Windows Event Viewer for any critical errors or warnings that could provide more insight into the shutdowns.

In conclusion, your situation requires a methodical approach to isolate the cause. If replacing the PSU is the next step, the aforementioned models are recommended based on their compatibility with your system’s specifications and their reputation for reliability. Always ensure that any new hardware is installed correctly and that all cables are securely connected.

— : Best PSU For Ryzen 5 7600 In 2023 – Silent PC Review : Choosing the Best Power Supply for AMD’s Ryzen 5 7600X CPU – TechReviewer

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