Practical testing …
There were no problems whatsoever with the installation and the cabling during our test. All plugs were neatly fitted and the cables were easy to route.
Since there is no selector switch for the mains voltage, you can’t go wrong here 😉
To check the quality of the power supply, we used the program HWiNFO to look at the voltages at no load and under load. To be able to load the CPU and the graphics card separately, we chose Prime 95 as CPU stress test and the Heaven Benchmark for the graphics card.
HWiNFO und Prime 95 können auch bei uns im Overclocking Software Bereich heruntergeladen werden.
Testsystem …
Our test system consists of the following components
| AMD Mainboard | ASUS TUF B450M-Pro Gaming |
| CPU | Ryzen 5 2600 @ 4,1GHz |
| RAM | 16 GB (2×8) DDR4-3333MHz CL16 |
| Graphics card | AMD Radeon RX580 8GB |
| Chassis | Cooler Master C700P Black Edition |
| PSU | Cooler Master Reactor Gold 750 |
The voltages …
Before we look at the voltages in detail, let’s have a look at the voltage tolerances according to the ATX specification. These are for the +5V and +12V line each +/-5% of nominal value, which results in the following limits. The power supply color codes and pin assignments are listed in our forum at PC power supply pin assignment.
| Voltage | Tolerance | Minimum | Maximum |
| +3.3V | ±5% | +3.14V | +3.47V |
| -5V | ±10% | -4.5V | -5.5V |
| +5V | ±5% | +4.75V | +5.25V |
| -12V | ±10% | -10.8V | -13.2V |
| +12V | ±5% | 11.4V | 12.6V |
Leerlaufwerte …
In idle mode, the CPU and the graphics card together require less than 40 watts. The voltages determined during this process are just above the nominal voltage.
Voltages under full load …
Finally, we push our system to its limits by launching the Heaven graphics benchmark in addition to Prime 95. Now the power supply has to deliver about 300 watts of power for the entire system. But even this load does not provide a great challenge for the Cooler Master Reactor Gold 750 power supply. The 12V rail does not even drop 0.05V below the nominal voltage. The 5V rail drops only very briefly by 0.07V, but then regulates constantly to 4.96V. These are really impressive stable values and far away from the limits of the allowed tolerances.
How many Euros in electricity costs for an economical Silent PC or a real gaming monster can be calculated with our PC power cost calculator:
Interactive power consumption Calculator
We now come to our conclusion …