Efficiency

Using the efficiency results from the previous page, we plotted a chart showing the GS 650's efficiency at low loads and loads equal to 20% -100% of the PSU's maximum-rated load.



At light loads, the 650 GS proved to be highly efficient. It was also just as efficient as other Gold-certified units in its category with normal loads.

Efficiency at Low Loads

In the next tests, we measured the efficiency of the GS 650 at loads much lower than 20% of its maximum-rated load (the lowest load the 80 Plus Standard measures). The loads we dialed were 40 W, 60 W, 80 W, and 100 W (for PSUs with over 500 W of capacity). This is important for settings where the PC is in idle mode with Power Saving turned on.


As has already been mentioned, efficiency was very high, and the fan spun at rather low speeds despite high operating temperatures, which kept noise output at equally low levels.

5VSB Efficiency

The ATX specification states that 5VSB standby supply efficiency should be as high as possible and recommends 50% or higher efficiency with 100 mA of load, 60% or higher with 250 mA of load, and 70% or higher with 1 A or more of load.

We will take four measurements: one at 100, 250, and 1000 mA, each, and one with the full load the 5VSB rail can handle.


Efficiency on the 5VSB rail was decent; however, we would like to at least see one reading above the 80% mark.

Power Consumption in Idle & Standby

In the table below, you will find the power consumption and voltage values of all rails (except -12V) when the PSU is in idle mode (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).


Vampire power was very low and will be even lower with 115 VAC.

Fan RPM, Delta Temperature & Output Noise

The cooling fan's speed (RPMs) and the delta difference between input and output temperature are illustrated in the following chart. The following results were obtained at 38°C-45°C ambient.



A chart that shows the cooling fan's speed (RPMs) and the output noise follows. We measure the fan's noise from one meter away, inside a small custom-made anechoic chamber whose internals are completely covered in specialized soundproofing material (Be Quiet! Noise Absorber Kit). Background noise inside the anechoic chamber was below 20 dBA during testing, and the results were obtained with the PSU operating at 38°C-45°C ambient.



The following graph illustrates the fan's output noise throughout the PSU's entire operating range. The same conditions as for the above graph apply to our measurements, but the ambient temperature was in-between 28°C and 30°C.



As you can figure out by looking at the graph above, passive mode didn't last for very long. Seasonic could make it last much longer without compromising the unit's reliability. Also, at up to around 350 W, the PSU is silent enough; however, the fan starts to spin faster after 350 W, which increases noise levels to a point that won't satisfy users looking for a dead-silent experience at normal operating temperatures.