Efficiency

Using the efficiency results from the previous page, we plotted a chart showing efficiency of the Leadex-1200 at low loads and at loads equal to 20%-110% of the PSU's maximum-rated load.



The Leadex-1200 performed well at low loads; that is, for its high capacity. It managed to outperform its smaller brother with 1000 W capacity and achieved a very high efficiency score with normal loads, which placed it near the top of the corresponding graph; with minor differences to the unit that took first place.

Efficiency at Low Loads

In the next tests, we measured the efficiency of the Leadex-1200 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 a capacity over 500 W). This is important for settings where the PC is in idle mode with Power Saving turned on.

As with every other unit utilizing this Leadex platform, our laboratory-grade power meter went crazy, showing significant deviations in AC wattage consumption. We were only able to calculate this unit's efficiency levels because of the custom-made software that controls all of our equipment. With 40 W load, efficiency was close to 75%, a very good reading for such a strong unit. Efficiency even broke 80% with 20 W, which makes the Leadex-1200 very efficient at such low loads.

5VSB Efficiency

The ATX spec 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 cannot keep up with the unit's overall performance, and we strongly suggest SF design a fresh rail that is stronger and more efficient if they want to catch up with the competition in this area.

Power Consumption in Idle & Standby

In the table below, you will find the power consumption and the 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).

Phantom power was lower than 0.5 W, so the PSU meets the 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-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 1 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 30 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 of the above graph apply to our measurements, but the ambient temperature was between 28°C and 30°C.



The unit's passive operation didn't last for long, but the fan operated at low enough RPM throughout most of the unit's operational range. The fan was noisy at full load, but it still produced less than 50 dBA, which means that it never spun at full speed.