Efficiency

Using the efficiency results from the previous page, we plotted a chart to show the P2-1200's efficiency at low loads and loads equal to 20%-100% of the PSU's maximum-rated load.



The P2-1200 achieved a pretty high efficiency score with both low and normal loads. At low loads, it took the lead from Seasonic's top platform (XP2), and its performance was on par with it with normal loads. Super Flower obviously did wonders with the platform, and the ripple results will definitely confirm this.

Efficiency at Low Loads

In the next tests, we measured the P2-1200's efficiency with loads well below 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.


Our power analyzer again picked up on large deviations with low loads; however, our sophisticated monitoring software allowed us to take accurate readings. The P2-1200 is generally very efficient with even such low loads—loads well below 10% of its max-rated-capacity.

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.


The 5VSB rail is probably this PSU's Achilles' heel because it is both weak and inefficient. Super Flower should look into this matter to provide an upgraded 5VSB circuit with future platforms. It is a shame that such a high quality unit features a mediocre 5VSB rail.

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 on 5VSB).


Vampire power was very low and easily meets ErP Lot 6 2013 requirements.

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-47°C ambient.



A chart that shows the cooling fan's speed (RPMs) and the output noise follows. We measure the fan's output noise at a distance of 1 meter, 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-47°C ambient.



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



At low loads and with the ECO mode enabled, the fan doesn't spin at all, which made the PSU incredibly quiet. However, the fan makes its presence felt once it spins up and is rather annoying at high loads.