Zalman ZM850-HP and ZM1000-HP

Efficiency and PFC

First of all the efficiency is great. With 230VAC it stays just above 85% from 180W to 700/800W of load, which is really good for a power supply. With lower input such as 120VAC it unfortunately cannot reach that same level of performance, but 83% at low load, 85% with medium load, and 82% with full load are also good results. The 1000W unit performs equally well in comparison to the 850W version, since it has almost the same efficiency with lower loads. The highest score today is 87% efficiency, reached by the 850W unit at around 400W of load and by the 1000W unit with 500W of load.

The power factor correction as usual doesn't look so good with higher input voltage. It reaches a reasonable level at high loads but it needs a long time to get on track. With 90 and 120VAC it looks quite different. Here it starts high and stays high as it should.