Test Setup

All measurements are performed utilizing a custom designed and built load tester, called Faganas, which is able to stress PSUs up to 1800 Watts. We also use a DS1M12 (Stingray) 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 three electronic loads (Array 3711A, 300W), a Rigol 1052E oscilloscope and a CEM DT-8852 sound level meter. In the near future we plan to acquire six additional loads to complete our new test set up, which with the help of our custom built software will have the same capabilities with the, ultra expensive, Chroma ATEs. In this article you will find more details about our equipment and the review methodology we follow.

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), when compared with the voltage values at 60W load.

Efficiency Chart

In this chart you will find the efficiency of the ZX Series 1250W 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 ZX Series 1250W. 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 the maximum load that our tester can apply to these rails, 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 minimum.


The PSU delivered its full power even at above 50°C ambient. Efficiency is high at all loads but cannot reach the efficiency levels of similar capacity PSUs that utilize LLC resonant converter topologies (e.g. Antec HCP-1200, Corsair AX1200). Voltage regulation at +12V and 5V registered under 3% deviation and at 3.3V under 4%. Deviation at +12V may look a bit high, at least compared to other PSUs we have previously tested, but you should keep in mind that we loaded the specific rail up to 99A at 100% load test and up to 106.4 at CL2 test. In a normal PC you won't load +12V as much unless you have three hi-end VGAs and a highly overclocked CPU under the hood running at full load. Finally the PF readings were a little lower than usual, but we consumers pay for reactive power only and not for apparent so this is not something to lose your sleep over it.

Efficiency at Low Loads

In the next tests, we measure the efficiency of ZX Series 1250W 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 (approximately) 40, 65 and 90W. This is important for scenarios in which a typical office PC is in idle with power saving turned on.


At low loads efficiency, as expected, doesn't go above 80%. However we have a 1250W capacity PSU here and running it with so small loads is like buying a Ferrari and use it for pizza delivery. So if you plan to power an Atom or Brazos platform you better find another PSU. As for PF readings these were a little lower than usual, again.

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).


In standby mode power consumption is under 1W so the PSU is ErP Lot 6 compliant.