The 80 PLUS certification measures efficiency at 20-, 50- and 100-percent load of the PSU's max-rated capacity up to the Gold efficiency certifications. For the Platinum and Titanium levels, they also measure efficiency with 10 percent of the PSU's max-rated capacity load.
Simply put, if a PSU has an 80 PLUS certification, then it must have the equivalent efficiency required by the corresponding certification. However, 80 PLUS measures at a mere 23 °C (73.4 °F) ambient, whereas we measure efficiency at a higher ambient temperature. This means that, in many cases, a PSU that is certified to a certain efficiency category fails to deliver the same efficiency at higher temperatures in our tests.
Besides 80 PLUS, there is also the Cybenetics efficiency and noise measurements standard, testing with more than 1450 different load combinations at higher temperatures (30 °C +-2°C) for more accurate results. Cybenetics has evaluated more than 1,000 PSUs so far, providing full evaluation reports on its database.
In our reviews, we measure efficiency with a super light load of 2% of the PSU's max-rated capacity, at light loads from 20W up to 80W, and at normal loads (10%-110%).
The ATX specification also states that the efficiency of the 5VSB rail should be measured, too. In the table below, you will find the minimum 5VSB efficiency levels that the ATX specification recommends.
Recommended System DC And AC Power Consumption
|≤0.225W||< 0.5W to meet 2013 ErP Lot 6 requirement (100V~240V)|
|≤0.45W||< 1W to meet ErP Lot 6 requirement (100V~240V)|
|≤2.75W||< 5W to meet 2014 ErP Lot 3 requirement (100V~240V)|
Testing in Standby Mode
In 2010, the European Union released a guideline on Energy Related Products (ErP Lot 6), which states that every electronic device should have below 1W power consumption in standby mode. In 2013, this limit was further reduced to 0.5W. The same year, the EU also released the ErP Lot 3 guideline for computers and computer servers.
This is why we measure the consumption of a PSU in standby mode, which is something that would be difficult without our monitoring software since the readings at such low consumption levels have significant fluctuations. We have to average them over a significant period of time to provide enough accuracy.
MORE: Best Power Supplies