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Efficiency
Our efficiency testing procedure is detailed here.
Using results from the previous page, we plotted a chart showing the efficiency of the SF600 Platinum at low loads, and loads from 10 to 110 percent of its maximum-rated capacity.
The SF600 Platinum achieves amazing efficiency levels under both light and normal loads. It is nice to see a platform featuring high efficiency along with tight load regulation since in some cases the engineers have to sacrifice a percentage of load regulation, in order to increase efficiency.
Efficiency At Low Loads
In the following tests, we measure the efficiency of the SF600 Platinum at loads significantly lower than 10 percent of its maximum capacity (the lowest load the 80 PLUS standard measures). The loads we dial are 20, 40, 60, and 80W. This is important for representing when a PC is idle, with power-saving features turned on.
| Test # | 12V | 5V | 3.3V | 5VSB | DC/AC (Watts) | Efficiency | Fan Speed (RPM) | PSU Noise (dB[A]) | PF/AC Volts |
| 1 | 1.197A | 0.495A | 0.476A | 0.199A | 19.568 | 73.730% | 0 | <6.0 | 0.834 |
| 12.088V | 5.054V | 3.356V | 5.027V | 26.540 | 115.06V | ||||
| 2 | 2.462A | 0.990A | 0.986A | 0.398A | 40.043 | 83.180% | 0 | <6.0 | 0.912 |
| 12.078V | 5.053V | 3.353V | 5.022V | 48.140 | 115.06V | ||||
| 3 | 3.652A | 1.484A | 1.461A | 5.018A | 59.511 | 86.659% | 0 | <6.0 | 0.960 |
| 12.079V | 5.053V | 3.353V | 5.018V | 68.673 | 115.07V | ||||
| 4 | 4.909A | 1.980A | 1.970A | 0.798A | 79.910 | 88.494% | 0 | <6.0 | 0.953 |
| 12.080V | 5.052V | 3.353V | 5.013V | 90.300 | 115.06V |
Under light loads we measure high efficiency, with the power supply operating in passive mode throughout all tests.
5VSB Efficiency
The ATX specification (revision 1.4), along with CEC, ErP Lot 3 2014 and ErP Lot 6 2010/2013, states that the 5VSB standby supply efficiency should be as high as possible, recommending 75 percent or higher with 550mA, 1A, and 1.5A of load.
The supply should also achieve higher than 75% efficiency at 5VSB under full load, or with 3A if its max current output on this rail is higher than 3A.
We take six measurements: one each at 100, 250, 550, 1000, and 1500mA, and one with the full load the 5VSB rail can handle.
| Test # | 5VSB | DC/AC (Watts) |
Efficiency | PF/AC Volts |
| 1 | 0.100A | 0.504 | 71.693% | 0.099 |
| 5.031V | 0.703 | 115.06V | ||
| 2 | 0.250A | 1.258 | 80.076% | 0.196 |
| 5.029V | 1.571 | 115.06V | ||
| 3 | 0.550A | 2.764 | 85.072% | 0.310 |
| 5.024V | 3.249 | 115.06V | ||
| 4 | 1.000A | 5.018 | 84.993% | 0.391 |
| 5.017V | 5.904 | 115.06V | ||
| 5 | 1.500A | 7.515 | 83.891% | 0.435 |
| 5.009V | 8.958 | 115.06V | ||
| 6 | 2.500A | 12.485 | 83.910% | 0.473 |
| 4.993V | 14.879 | 115.06V |
The 5VSB rail is among the best we have encountered so far. Besides good load regulation it also achieves sky high efficiency levels.
Power Consumption In Idle And Standby
In the table below, you’ll find the power consumption and voltage values of all rails (except -12V) when the PSU is idle (powered on, but without any load on its rails), and the power consumption when the unit is in standby mode (without any load, at 5VSB).
| Mode | 12V | 5V | 3.3V | 5VSB | Watts | PF/AC Volts |
| Idle | 12.062V | 5.051V | 3.349V | 5.032V | 7.094 | 0.475 |
| 115.1V | ||||||
| Standby | 0.049 | 0.007 | ||||
| 115.1V | ||||||
The vampire power levels are kept low, and this plays a key role in the 5VSB rail's efficiency under light loads.
Fan RPM, Delta Temperature, And Output Noise
Our mixed noise testing is described in detail here.
The first chart below illustrates the cooling fan's speed (in RPM), and the delta between input and output temperature. The results were obtained at 37°C (98.6°F) to 47°C (116.6°F) ambient temperature.
The next chart shows the cooling fan's speed (again, in RPM) and output noise. We measure acoustics from one meter away, inside a hemi-anechoic chamber. Background noise inside the chamber is below 6 dB(A) during testing (it's actually much lower, but our sound meter’s microphone hits its floor), and the results are obtained with the PSU operating at 37°C (98.6°F) to 47°C (116.6°F) ambient temperature.
The following graph illustrates the fan's output noise over the PSU's operating range. The same conditions of the above graph apply to our measurements, though the ambient temperature is between 30°C (86°F) to 32°C (89.6°F).
The semi-passive mode doesn't last long, however you should keep in mind that this is a SFX unit so it is much harder to retain the passive operation. The good news is that for most of the time the fan spins at low speeds, producing equally noise output. Even with close to the max rated output the noise stays below 35 dB(A).
