Symptoms
- Computer restarts suddenly during games, video rendering, or other demanding tasks
- No blue screen appears, just an instant restart
- Idle and light use are completely stable
- Restarts happen more often in summer or a warm room
Likely causes
- CommonPower supply unable to sustain the load the components draw during heavy tasksThis is especially likely if the PSU is older, undersized, or of lower quality.
- CommonCPU or GPU overheating under sustained loadThermal protection can trigger a hard restart to prevent damage.
- PossibleUnstable overclock on the CPU, GPU, or RAMOverclocked settings that are borderline can fail specifically under full load.
- Less commonAging capacitors on the motherboardLess common today but can cause instability under load on older boards.
What to do
- Reset any CPU, GPU, or RAM overclocks to default settings and see if the restarts stop.
- Monitor CPU and GPU temperatures during the demanding task to check for thermal shutdown-range readings.
- Check the power supply's wattage rating against the total draw of your CPU and GPU under load, especially with a newer, more powerful GPU.
- Clean dust from fans and heatsinks to rule out an airflow-related heat buildup.
- If you have access to another PSU of adequate wattage, test with it temporarily to see if restarts stop.
- If restarts persist even at stock settings with good cooling and an adequate PSU, have the power supply and motherboard tested professionally.
Tools and parts
- Temperature and power monitoring software
When to call a pro
If restarts under load continue despite normal temperatures and an adequately rated PSU, a technician can test the power supply and motherboard under real load conditions.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.