Effective PSU evaluation requires specialized equipment and controlled procedures, far beyond basic multimeters and ad-hoc load tests. The setup used incorporates programmable electronic loads, precision oscilloscopes, power analyzers, thermal/acoustic instrumentation, and custom fixtures of our own design to ensure repeatable and standards-compliant results.
Electronic Loads
Two high-precision Maynuo M9714 (1200 W) and two Maynuo M9711 (150 W) programmable DC loads are used. This configuration allows up to 2400 W to be drawn from the +12 V rails and 150 W from each of the +3.3 V and +5 V rails. Their fast response enables both static and transient load testing. We also have two Vantec CA5015 loads (150W each) for secondary tests (e.g. 5VSB checks, etc).
Oscilloscope
A Hantek DSO4102S is used, with a maximum bandwidth of 100 MHz and digital acquisition capabilities.
A Rigol DS5042M digital oscilloscope is also employed, featuring 40 MHz bandwidth and a 500 MSa/s real-time sampling rate. Both are suitable for ripple and noise testing as per the ATX design guide.
Power Measurement
Input power is monitored with an Extech 380803 power analyzer, which provides true RMS readings and accounts for harmonic distortion generated by switching PSUs. The AC input is regulated via a 3000 VA VARIAC, maintaining precise 230 V/50 Hz conditions. We also test the units at 115 V/50 Hz. At present, 110 V/60 Hz testing is not supported due to the absence of a high-output programmable AC source.
Thermal Monitoring
Thermal performance is tracked using UNI-T UT-325 digital thermometers with four probes: ambient air, PSU exhaust, and primary/secondary heatsinks. This allows detailed temperature mapping under different operating conditions.
Acoustic Testing
Fan speed is recorded with a laser tachometer, while acoustic output is measured using an Extech HD600 sound level meter. Since active load equipment generates noise, acoustic testing is performed separately with the PSU fan powered by a custom fanless DC power supply. Noise is correlated against RPM data, with a measurement environment baseline of ~30.4 dB(A).
Environmental Simulation
A custom-built hot box simulates in-case thermal conditions. It consists of a closed chamber with a controlled air-heating element, managed via a DAQ and software. Tests are performed at both room temperature (~25 °C) and elevated hot box conditions (45–50 °C) to evaluate efficiency and stability under realistic system thermals.
Test Procedures
All testing follows Intel’s ATX Design Guide and the Generalized Test Protocol for Internal AC-DC and DC-DC Power Supplies, ensuring standardized methodology. Where guidelines are insufficient (e.g., transient and cross-load testing), custom procedures are applied, such as loading rails independently to simulate demanding scenarios. Efficiency is tested from 5% to 100% load, exceeding the standard 20%–100% certification points to reflect modern idle power behavior.
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