5-way High-End 1KW+ PSU Round-Up
Test Results – Efficiency & PFC
While voltage stability and output certainly carries a lot of weight for the consumer considering the purchase of a new PSU, Efficiency (which is quite often directly related to the noise and heat output of a unit) should also be taken into account. In general terms, efficiency is a measure of how much power was lost during the conversion between AC and DC voltages inside the PSU. The higher the efficiency percentage, the less power was lost; resulting in energy savings and often a cooler running PSU.
As mentioned earlier in the review, Enermax were keen to tell us about the work they’d put into ensuring that their Revolution 85+ PSU was one of the most efficient on the market, and this has certainly paid off. Sitting unchallenged at the top of the efficiency graph with results nearing almost 90%, Enermax have certainly got this one in the bag.
Both Cooler Master and Corsair sit roughly in the middle of the results with efficiency averaging between 84-87%, while the Be-Quiet unit has a fairly mediocre starting at 83% efficiency while under medium load, but quickly increases this 85% once additional load is applied.
Sitting at the bottom of the graph is the Silverstone Zeus which manages 82% efficiency at 50% and 75% load levels, but dips down to just under 81% efficiency at 100% load.
Interestingly the underdog in most of the previous results is the clear winner when it comes to PFC. Managing between 0.98 and 0.99 throughout the testing, the Silverstone Zeus clearly has the most advanced Active PFC circuitry of all the PSU’s on test. This is more than likely down to the Zeus’s enterprise server background, where organisations with large datacentres are often charged by electricity suppliers for not only their power consumption but also for their overall Power-Factor.
However, not far at all behind the Silverstone is the Enermax. Managing a 0.96 PF at 50% load, this quickly rises to 0.98 at 75% and 100% loads. The Be-Quiet unit also joins the Enermax at 50% and 100% load levels, but interestingly dips to 0.95 at 75% load.
As already mentioned back on the testing procedure page, the ambient noise levels at both of the test facilities prevented us from obtaining any useful dBA measurements from the units. However, during the testing each of the PSU’s were given a score from 1 to 5 (5 being the loudest) based on personal experience.
