Test Setup

All measurements are performed utilizing ten electronic loads (seven Array 3711A, 300W each, and three Array 3710A, 150W each), which are able to deliver over 2500W of load and are controlled by a custom made software. We also use a Picoscope 3424 oscilloscope, a CHY 502 thermometer, a Fluke 175 multimeter and an Instek GPM-8212 power meter. Furthermore, in our setup we have included a wooden box, which along with a heating element is used as a Hot Box. Finally, we have 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, if the manufacturer states that the maximum operating temperature of the test unit is only 40°C then we try to stay near this temperature, otherwise we crank up the heat inside the hotbox up to 45-50°C.

Voltage Regulation Charts

The following charts show the voltage values of the main rails, recorded over a range from 60W 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 SPH-1050 at low loads and at loads equal to 20-100% of PSU's maximum rated load.

Voltage Regulation and Efficiency Measurements

The first set of tests reveals the stability of voltage rails and the efficiency of SPH-1050. The applied load equals to (approximately) 20%, 40%, 50%, 60%, 80% and 100%, of the maximum load that the PSU can handle. In addition, we conduct two more tests. In the first we stress the two minor rails (5V & 3.3V) with a high load, while the load at +12V is only 2A and in the second test we dial the maximum load that +12V can handle while load at minor rails is minimal.


Efficiency is quite high, although not the highest we have seen from a Gold unit and voltage regulation in general is not so tight. Especially the 3.3V rail registers large voltage drops, as the load increases, but thankfully it manages to stay within 5% regulation. During 20% and CL1 load tests the unit went fanless so naturally the input temperature (measured on the top of the unit, where the fan is installed) was much higher than the output, since hot air rises. What troubled us the most was that during CL1 test, although the unit was very hot, the fan didn't automatically start to protect the internals from overheating neither the Over Temperature Protection activated. Also another interesting thing was that when we suddenly switched from the full load test, where the fan was working at full RPM, to 20% or CL1 test then the fan stopped to spin, although the internal temperature of the unit was already high, leading to dangerously high temperatures in the internals. Enhance/Coolermaster definitely need to tune the transition to fanless mode and make it more temperature dependent rather than load dependent, in order to protect the components of the PSU from excess heating/stressing. Also the Over Temperature Protection trigger point needs to be lowered, in order to efficiently protect the unit. Regarding noise, as we already stated despite the high operating temperature at 20% and CL1 tests the unit was totally inaudible since the fan didn't spin. During 40%-60% load tests the fan was spinning at low speeds so it was very quiet and at 80-100% tests the fan was at max RPM producing a very loud noise (59dBA at 0.5m distance). Out of curiosity (and of course to further inform you) we ran some extra full load tests at room temperature during which we found out that at normal ambient the fan doesn't spin at max RPM, producing much less noise, so don't worry, you will get 59dBA only if you manage to stress the unit like we did (full load in an oven/hot box).

Efficiency at Low Loads

In the next tests, we measure the efficiency of SPH-1050 at loads much lower than 20% of its maximum rated load (the lowest load that the 80 Plus Standard measures). The loads that we dial are 40, 60, 80 and 100W (for PSUs with over 500W capacity). This is important for scenarios in which a typical office PC is in idle with power saving turned on.


Efficiency at low loads is not high but we didn't expect to see anything different from a 1050W unit, even if this is Gold rated. With 80W load we get nearly 80% and only with 100W the unit manages to achieve well over 80% efficiency.

5VSB Efficiency

ATX spec states that the 5VSB standby supply's efficiency should be as high as possible and recommends 50% or higher efficiency with 100mA load, 60% or higher with 250mA load and 70% or higher with 1A or more load.
We will take four measurements, three at 100 / 250 / 1000 mA and one with the full load that 5VSB rail can handle.


At 5VSB, efficiency is constantly above the corresponding thresholds, although at tests #3 and #4 it surpasses 70% only by a small percent.

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 (On but without any load at its rails) and the power consumption when the PSU is in standby (without any load at 5VSB).


Phantom power is a low as 0.3W so the PSU easily meets the ErP Lot 6 2010 (and the future 2013) requirements. As it seems these standby PWM controllers, utilized on almost all contemporary PSUs, are really worth their money.