[Help] PC Randomly Shutting Down — Even When Idle — Need Help Diagnosing

Understanding and Diagnosing Unexpected PC Shutdowns During Idle and Light Use

Experiencing random shutdowns on a personal computer can be a frustrating ordeal, especially when they occur without warning and during low-stress activities. If you’re facing similar issues, you’re not alone. This article aims to delve into common causes and troubleshooting steps to help identify and resolve such problems effectively.

Case Overview

Consider a typical scenario: a user reports that their desktop PC intermittently powers off without notice, even during minimal activity like browsing or playing non-modified, lightweight games such as Minecraft. These shutdowns happen unexpectedly, without blue screens or system alerts, and sometimes result in booting difficulties—no display output, unlit peripherals, requiring HDMI re-plugging to restore normal operation.

System Specifications

For context, the affected setup includes:

Processor: AMD FX 6300
Motherboard: MSI A970 Gaming (Carbon)
RAM: 16GB DDR3
Graphics Card: XFX RX 580
Power Supply: Corsair CV550 (550W)
Storage: 128GB SSD and 1TB HDD
Monitor: MSI MP243X (100Hz) via HDMI

The user has performed stress tests on both the CPU (AIDA64) and GPU (FurMark), which report stable temperatures (~82°C CPU, ~84°C GPU), consistent voltages, and normal power draw. However, shutdowns are observed only during typical use cases—gaming or browsing—not during testing phases.

Potential Causes and Troubleshooting Strategies

Power Supply Issues
Voltage Stability: Even if the PSU is rated at 550W, it may be delivering inconsistent power, especially under load or due to aging components.
Solution: Test with a known-good, higher-capacity PSU if available. Alternatively, use a power supply tester or multimeter to monitor output voltages under load.
Thermal and Cooling Concerns
Check for Overheating: While stress tests show acceptable temperatures, real-world scenarios might cause hotspots or thermal throttling.
Solution: Ensure all cooling fans are functioning, heatsinks are properly seated, and airflow isn’t obstructed. Use monitoring tools to record temperatures during idle and light use.
Hardware Compatibility and Faults
Memory and Motherboard: Faulty RAM or motherboard issues can lead to system instability.
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