To test the power supply unit, we will not connect it to an everyday system as we would be unable to know the exact load that we would provide and wouldn’t be able to vary the load. Instead we will use power resistors which are nothing more than normal resistors but capable of consuming a good amount of power. How much power depends on the resistance and capability of the resistor, and can be easily calculated by Ohm’s law (Amperes = Voltage / Resistance, Power = Voltage * Amperage).

Hence for example a 1Ohm resistor attached to the 3.3V line will allow 3.3A through it and consume about 10W of power. When adding two of these resistors in parallel, you double the power consumption and allow 20W to be consumed as you halve the resistance this way. Adding more will increase the power consumption. Of course that is not entirely accurate on paper as the fault tolerance of these resistors is high and almost none are exact to their resistance specifications, but after using them we could calculate how much power each bunch of them would consume accurately. This way we can add fake load to any power supply unit, and on any power line we wish with good accuracy.

For testing the Spire Rocketeer VI, taking into account its design and power specifications, we set the fans at full speed and took the following steps:

Total Load	3.3V Load	5V Load	12V-1 Load	12V-2 Load
33% (~200W)	15A (50W)	10A (50W)	4A (48W)	4A (48W)
50% (~300W)	15A (50W)	18A (90W)	7A (84W)	6A (72W)
75% (~450W)	15A (50W)	18A (90W)	13A (156W)	13A (156W)
100% (~600W)	25A (83W)	30A (150W)	15A (180W)	15A (180W)
105% (~650W)	25A (83W)	32A (160W)	17A (204W)	17A (204W)

dont have flash installed? then click here for a jpeg

The room temperature when the test took place was 28 Celsius degrees, a rather warm summer day. Under these conditions, the Spire Rocketeer performed admirably. The power fluctuations are minor and unimportant, while the unit was able to work above its full load and near its peak load continuously without any problems. We tried loading it more, but its overload protection circuit would kick in and shut the unit down after a few seconds. We also tried testing the unit with the fans set to thermal control in order to find out if the unit remained silent under high loads. We found the unit able to remain almost silent up to about 70% load, at this level the unit got quite warm but the fans would not speed up.