Test Setup

All measurements were performed using ten electronic loads (seven Array 3711A [300 W each] and three Array 3710A [150 W each]) that are able to deliver over 2500 W of load and are controlled by a custom-made software. We also used a Picoscope 3424 oscilloscope, a CHY 502 thermometer, a Fluke 175 multimeter, and an Instek GPM-8212 power meter. Furthermore, in our setup, we included a wooden box, which, along with a heating element, was used as a hot box. Finally, we had at our disposal four more oscilloscopes (Rigol 1052E and VS5042, Stingray DS1M12, and a second Picoscope 3424) and a CEM DT-8852 sound level meter. In this article, you will find more details about our equipment and the review methodology we follow. Finally, we conduct all of our tests at 40 - 45°C ambient, in order to simulate with higher accuracy the environment seen inside a typical system, with the 40 - 45°C being derived from a standard ambient assumption of 23°C, and with 17 - 22°C added for the typical temperature rise within a system.

Voltage Regulation Charts

The following charts show the voltage values of the main rails, ranging from 60 W to the maximum specified load, and the deviation (in percent) for the same load range.

5VSB Regulation Chart

The following chart shows how the 5VSB rail deals with the load we throw at it.

Efficiency Chart

In this chart, you will find the efficiency of the MK3S1200 at low loads and at loads equal to 20-100% of the PSU’s maximum rated load.

Voltage Regulation and Efficiency Measurements

The first set of tests revealed the stability of the voltage rails and the efficiency of the MK3S1200. The applied load was equal to (approximately) 20%, 40%, 50%, 60%, 80%, and 100% of the maximum load that the PSU can handle. In addition, we conducted two more tests. In the first test, we stressed the two minor rails (5V and 3.3V) with a high load, while the load at +12V was only 2 A, and, in the second test, we dialed the maximum load that the +12V rail could handle, while the load on the minor rails was minimal.

The PSU easily delivered its full power up to 47°C ambient with minimal noise output. Its fan is one of the most silent ones we have ever encountered in a PSU of this category (and not only this category). The unit operated in silent/fan-less mode up to 40% load, causing the intake temperature, measured at the top of the PSU, to be higher than the temperature measured at the exhaust (front side). This simply happens because hot air is lighter than cold air and moves upwards.
Voltage regulation is decent overall, while efficiency is definitely top notch throughout the entire load range. It seems that Super Flower focused mostly on providing the best possible efficiency and not a tight voltage regulation.

Efficiency at Low Loads

In the next tests, we measured the efficiency of the MK3S1200 at loads much lower than 20% of its maximum rated load (the lowest load that the 80 Plus Standard measures). The loads that we dialed were 40, 60, 80, 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.

This PSU behaved like a smaller capacity Platinum one at low loads since it managed to achieve very high efficiency readings regardless of what minimal loads we dialed. It's very impressive to see a 1.2 kW PSU pass the 80% mark so easily with a 60 W load.

5VSB Efficiency

The ATX spec states that the 5VSB standby supply's 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: three at 100, 250, and 1000 mA, and one with the full load that the 5VSB rail can handle.

With the first two tests, efficiency is nothing to write home about since it merely passes the corresponding limits. The last two tests, however, are pretty high for the standards of this rail. The 5VSB rail registers a reading of well over 80% at full load.

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 is lower than the ErP Lot 6 2010 directive requirements, but a hair higher than the limit of the ErP Lot 6 2013. Nevertheless, we should also take the margin of error with our power meter into account here since the measured reading exceeds the ErP2013 limit by only 0.02 W.