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Efficiency, Temperature And Noise
Efficiency
Our efficiency testing procedure is detailed here.
Using the results from the previous page, we plotted a chart showing the 550 GS' efficiency at low loads, and loads from 10 to 110 percent of the PSU's maximum-rated capacity.
Under both light and normal loads, the 550 GS enables high efficiency levels, which in both cases surpass the performance of Seasonic's G-550 V2, a supply that competes with EVGA's offering.
Efficiency At Low Loads
In the following tests, we measure the efficiency of the 550 GS at loads significantly lower than 10 percent of the device's maximum capacity (the lowest load the 80 PLUS standard measures). The loads we dialed were 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 | Power DC/AC | Efficiency | Fan Speed | Fan Noise | PF/AC Volts |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 1.193A | 0.491A | 0.475A | 0.195A | 19.69W | 72.39% | 600 RPM | 27.3 dB(A) | 0.892 |
| 12.237V | 5.092V | 3.367V | 5.093V | 27.20W | 114.9V | ||||
| 2 | 2.410A | 0.979A | 0.98A | 0.389A | 39.73W | 81.80% | 600 RPM | 27.3 dB(A) | 0.953 |
| 12.231V | 5.088V | 3.361V | 5.085V | 48.57W | 115.0V | ||||
| 3 | 3.633A | 1.466A | 1.488A | 0.590A | 59.85W | 85.79% | 600 RPM | 27.3 dB(A) | 0.978 |
| 12.223V | 5.084V | 3.355V | 5.075V | 69.76W | 115.0V | ||||
| 4 | 4.845A | 1.963A | 1.970A | 0.785A | 79.73W | 87.72% | 600 RPM | 27.3 dB(A) | 0.986 |
| 12.215V | 5.079V | 3.350V | 5.068V | 90.89W | 115.0V |
At light loads, the PSU offers high efficiency levels along with low noise output. In three out of the four light-load tests, efficiency easily passed the 80 percent mark. And with 80W load, we measured close to 88 percent efficiency, which is impressive.
5VSB Efficiency
The ATX specification states that 5VSB standby supply efficiency should be as high as possible, recommending 50 percent or higher efficiency with 100mA of load, 60 percent or higher with 250mA of load and 70 percent or higher with 1A or more of load.
We will take four measurements: one each at 100, 250 and 1000mA, and one with the full load the 5VSB rail can handle.
| Test | 5VSB | Power DC/AC | Efficiency | PF/AC (V) |
|---|---|---|---|---|
| 1 | 0.102A | 0.52W | 67.53% | 0.118 |
| 5.104V | 0.77W | 115.4V | ||
| 2 | 0.252A | 1.28W | 71.91% | 0.227 |
| 5.099V | 1.78W | 115.4V | ||
| 3 | 1.002A | 5.09W | 80.03% | 0.376 |
| 5.080V | 6.36W | 114.9V | ||
| 4 | 2.502A | 12.62W | 78.24% | 0.443 |
| 5.043V | 16.13W | 114.9V |
The 5VSB rail proves to be highly efficient, losing only to the high-end Seasonic fanless unit, which utilizes a higher-grade platform.
Power Consumption In Idle And Standby
| Mode | 12V | 5V | 3.3V | 5VSB | Power AC | PF/AC (V) |
|---|---|---|---|---|---|---|
| Idle | 12.241V | 5.100V | 3.377V | 5.106V | 6.54W | 0.549 |
| 115.2V | ||||||
| Standby | 0.11W | 0.019 | ||||
| 115.4V |
In the table above, 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 PSU is in standby mode (without any load, at 5VSB).
In all cases, energy consumption at standby was very low, easily meeting the ErP Lot 6 2013 requirements. At the same time, this helped achieve high efficiency levels on the 5VSB rail.
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 (RPMs), and the delta between input and output temperature. The results were obtained at 36 degrees C to 45 degrees C ambient temperature.
The next chart shows the cooling fan's speed (RPMs) and output noise. We measured acoustics from one meter away, inside a small, custom-made anechoic chamber with internals completely covered in sound-proofing material (be quiet! Noise Absorber kit). Background noise inside the anechoic chamber was below 18 dB(A) during testing, and the results were obtained with the PSU operating at 36 degrees C to 45 degrees C ambient temperature.
The following graph illustrates the fan's output noise over the entire operating range of the PSU. The same conditions of the above graph apply to our measurements, though the ambient temperature was between 28 degrees C and 30 degrees C.
As you can see from the graph above, the passive mode doesn't last long; however, the PSU's noise output was low enough up to around 200W to 250W. Above that, the noise output increased, entering the loud region with 350W and higher loads.
