The PSU boasts superb stability of the output voltages. The +12V diagram is a solid green field. The +5V voltage shows the biggest deflection, 4%, from the nominal value (the allowable maximum is 5%).
The most interesting part of the test is about the output voltage ripple. It’s all right with the high-frequency pulsation as it is much weaker than allowable.
The low-frequency ripple diagram recorded at maximum load still shows noise bursts with a duration of about 5 milliseconds each. This time, however, these bursts are within 25 millivolts, which is far below the allowable maximum (which is 50 millivolts for the +5V and +3.3V power rails and 120 millivolts for the +12V rail). So, I just want to congratulate Antec and Seasonic on having found a working solution of the problem!
The PSU uses an Adda AD0812HB-A71GL fan (80x80x25mm, 3010rpm). Its speed is constant at loads below 200W and then begins to grow linearly up to 2600rpm. The PSU is indeed very quiet at work. Its fan sounds like a barely audible whisper at loads below 300W.
The efficiency is 85-86% through the typical load range and lowers to 82% at near-maximum loads. The power factor is above 0.95 at typical loads as you can expect from a PSU with active Power Factor Correction.
So, Antec and Seasonic have successfully got rid of the problems the revision A3.1 Neo HE 550 had. Now it is a high-quality, stable and very quiet power supply capable of supporting a very advanced modern configuration.