Page 8 - Load testing the PSU (2)
So we know that a 5% fluctuation is perfectly acceptable and falls with ATX specification, so 12 Volts should remain between 11.4 - 12.6v as you can see the PSU when utilized stays FAR from that meaning that the PSU is functioning within ATX specified limits. Though 12V3 and 12V4 show a teeny weenie bit of fluctuation.
This makes sense, with the test platform we were able to push the PSU towards close to it's maximum advertised specifications.
During the load test several times I felt to see if the PSU was warm, it remained cold at all times. It feels like it's hardly doing anything at all.
Very notable is this; with a wattage meter we noticed that wattage did not peak over 500 Watts where other PSU's did have much higher peak loads. Now please remember what I told you about power efficiency. This PSU's efficiency is really good and it's showing. We estimate 84% efficiency.
Again, this was tested on a NVIDIA GeForce 8800 GTX (overclocked) SLI system with an overclocked (3GHz) Quad Core Q6600 processor. We wanted to go for 3-way SLI yet XFX insisted to have the GeForce Ultra's returned.
Let's have a look at sound ... um, yeah, I said that right.
Sound levels (dBA)
As usual we grabbed our dBa meter, enabled the PSU by hot-wiring it and started to listen if it made any significant noise. Short and simple it's really silent.
The human hearing system has different sensitivities at different frequencies. This means that the perception of noise is not at all equal at every frequency. Noise with significant measured levels (in dB) at high or low frequencies will not be as annoying as it would be when its energy is concentrated in the middle frequencies. In other words, the measured noise levels in dB will not reflect the actual human perception of the loudness of the noise. That's why we measure the dBa level. A specific circuit is added to the sound level meter to correct its reading in regard to this concept. This reading is the noise level in dBA. The letter A is added to indicate the correction that was made in the measurement.
It's amazing how silent this PSU actually is.
As always we measure 75 CM away from the product (usually the distance between you and a desktop computer), and yes .. this test is always a tad subjective yet we measured ~32 DBa and that's including surrounding noise levels, that's just perfect..
All in all, very silent and thus highly recommended to any of the audiophiles that like silence (yours truly included).
