Power supply

Step-by-step power supply check when buying or for yourself. Works for new and used PSUs.

1

Quick check

5 minutes

  1. Visual inspection

    Wires intact, no burning smell, the fan works (must spin at least at power-on).

  2. System stability

    The computer must not shut down or reboot by itself under load.

2

Medium check

10 minutes

  1. Software monitoring

    Check the 12V, 5V and 3.3V rail voltages in BIOS (Hardware Monitor) or via AIDA64/HWMonitor. Deviations must not exceed 5%.

3

Full check

20–30 minutes

  1. Load test

    OCCT (Power Supply section): max load on CPU and GPU at once, pushing the PSU to its limit.

  2. Physical check

    Use a multimeter or a dedicated PSU tester to measure voltages directly on the connectors (Molex, SATA, 24-pin).

Related checklists

CPUGraphics cardSSD/HDD

How to test tech before buying

Buying new or used tech always comes with risks: hidden defects, dead pixels, broken keys, a worn battery, cooling issues and other problems are not always visible during a casual inspection. FullTestPC provides detailed step-by-step guides to help you catch everything when checking devices. For each type of hardware — laptops, desktop PCs, monitors, keyboards, mice, headphones, GPUs, SSDs and HDDs, RAM, CPUs and power supplies — we have three levels of diagnostics: a quick 5–10 minute check with no software to install (visual inspection, basic functions), a medium 15–20 minute check using built-in Windows tools (battery reports, chkdsk, load tests) and a full 30–60 minute check using professional utilities like AIDA64, FurMark, CrystalDiskInfo, Victoria, TestMem5 and OCCT. This approach lets you adjust the depth of the check to the situation: a quick check is enough when buying from a store, a medium check when buying from a private seller, and a full stress test of all components for complete peace of mind. Many tests can be done right in the browser using our online tools (keyboard test, monitor dead pixel test, mouse and trackpad test), while the rest use standard or free programs. Following these checklists reduces the risk of buying a broken device and gives you confidence in its condition.