Efficiency

Using the efficiency results from the previous page, we plotted a chart showing the efficiency of the KL-C1200PL at low loads and at loads equal to 20% -100% of the PSU's maximum-rated load.



The efficiency levels of the KL-C1200PL manage to put other high-end, much more modern platforms to shame. We have to admit that this does look really weird - here is a platform featuring a CM6800TX controller and a double-forward topology that beats out platforms featuring more efficient topologies by design.

Efficiency at Low Loads

These tests measure the efficiency of the KL-C1200PL 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.

Efficiency under light loads is impressive! PSUs of a similar capacity are usually far less efficient at such loads under the same conditions.

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 isn't that efficient. We would at least like to see 80% efficiency in one of these tests.

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).

Our power meter measured less than 0.14 W vampire power, so the PSU won't have any problems with achieving 45% efficiency in standby with up to 0.225 W load at 5VSB.

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 36 °C - 45 °C ambient.



A chart that shows the cooling fan's speed (RPMs) and its output noise follows. We measure the fan's noise from a 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 this anechoic chamber was below 20 dBA during testing, and the results were obtained with the PSU operating at 36 °C - 45 °C ambient.



The following graph illustrates the fan's output noise throughout the PSU's entire operating range. The same conditions as in the above graph apply to our measurements, but the ambient temperature was in-between 30 °C and 32 °C.



With such high efficiency, a semi-passive mode would come in handy. It would drastically reduce output noise under light and moderate loads.