First identify the exact failure pattern
- Does the PC go completely black and stay off until the power button is pressed?
- Does it restart automatically?
- Does the picture disappear while fans and lights stay on?
- Does Windows freeze while the machine remains powered?
- Is there a blue screen or error message?
Why separate CPU, GPU, and combined-load tests
A machine can pass a CPU-only test and a GPU-only test but fail when both are loaded together. That can reveal interactions involving total power draw, motherboard power delivery, memory, cooling, or a marginal component that is not stressed enough in isolation.
Changing the workload and observing how the failure changes is useful evidence. It is more informative than assuming the graphics card or power supply is responsible because the problem happens during a game.
What to check before buying a power supply
- Verify temperatures and fan or pump operation.
- Check CPU and GPU power connectors and component seating.
- Review the PSU model, wattage, age, and GPU power recommendation.
- Test memory stability and BIOS defaults.
- Look for motherboard damage, loose screws, shorts, or damaged connectors.
- Remember that Event Viewer may not record a hard freeze or abrupt power loss.
When the PSU moves higher on the list
A power supply becomes more suspicious when the machine loses all power under combined load, its wattage or connector configuration is marginal, another known-good unit changes the behavior, or protection circuitry appears to be tripping. It should not be blamed solely because a game causes shutdowns.
Bottom line
Reproduce the exact failure, separate different workloads, monitor temperatures and power behavior, and replace parts based on evidence rather than cost or reputation.