How we test
For testing power supplies we utilise professional Stratron load generators, which allows us to put a load of up to 1600 watts on PSUs in our test lab. Each PSU we test in increments of 100 watts up to the maximum load. At each step we measure voltages on the different lines. The closer those measurements are to the official values of 3.3, 5 and 12V, the better. More than 5 percent deviation means not good. At each step we also measure the current from the socket with a professional Zes Zimmer ammeter. Based on this we calculate the efficiency. An oscilloscope allows us to measure the ripple, which are fluctuations in the direct current (dc) output of a power supply which has been derived from an alternating current (ac) source.
It should be noted that in all cases we draw 50 watts of current from the 3.3 and 5V lines, and the rest from the 12V lines. This is different than how the 80 Plus initiative or most manufacturers themselves test their power supplies, but is closer to real-world performance. In a PC all energy-consuming components (mainly the CPU and GPU) only utilise the 12V lines, and the 3.3 and 5V lines have a very limited role.
In addition to measurements with load, we also measure the current drawn from the socket without any load. It is important to know how much leakage current a power supply has.
The noise test we perform by connecting the power supply to two passively cooled systems, one with a 120 watt load and one with a 350 watt load. The noise is measured at a distance of 10 cm, perpendicular to the fan in the PSU.
The charts on the following pages compare the OCZ Fatal1ty 1000W with other recently tested power supplies with capacities between 900 and 1000 watts.