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 GS800 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 GS800. 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.


Although it's efficiency is only Bronze, the PSU registered very good readings at typical loads (40-50% of max rated capacity). Nevertheless with full load, efficiency took a significant hit dropping to 85%. The second remark we have to make is that although Corsair rated this unit at 40°C max, we managed to pull its full power even at 50°C without any problems. Nevertheless at these temperatures the fan runs annoyingly loud, which most likely will be intolerable for most users. More specific from 60% load and above the fan made its presence well felt during our test session.

Efficiency at Low Loads

In the next tests, we measure the efficiency of the GS800 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 very low loads is good enough since it doesn't fall below 70% even with 40W load. Also at the last two tests with 80W and 100W load it surpasses the 80% mark, something really good for an 800W capacity Bronze unit. Overall this PSU will save you some money from electricity bills even at below 100W loads.

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 the first two tests efficiency is surprisingly high since it passes the 70% mark while at the last two it is good too, although not so amazingly high. For this specific rail, over 75% efficiency is something worth mentioning.

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 definitely something to write home about, since it is almost zero. This unit passes even the future and stricter ErP Lot 2013 requirements and sets an example to follow for the rest manufacturers.