The Zalman ZM1200-EBT 1200W Power Supply Review

Cold Test Results

For the testing of PSUs, we are using high precision electronic loads with a maximum power draw of 2700 Watts, a Rigol DS5042M 40 MHz oscilloscope, an Extech 380803 power analyzer, two high precision UNI-T UT-325 digital thermometers, an Extech HD600 SPL meter, a self-designed hotbox and various other bits and parts. For a thorough explanation of our testing methodology and more details on our equipment, please refer to our How We Test PSUs - 2014 Pipeline post.

The energy conversion efficiency of the ZM1200-EBT in room temperature and for an input voltage of 230VAC does meet the expected 80Plus Gold standards, even if only barely. Our instruments recorded an efficiency of 90.1%, 92.4% and 90.1% at 20%, 50% and 100% load respectively, with the 80Plus directive requiring 90%/92%/90% for an 80Plus Gold certification with an input voltage of 230VAC. The average efficiency is 91.2% within the nominal load range (20% to 100% of the unit's capacity), a fair figure for an 80Plus Gold certified unit. The low load efficiency of the ZM1200-EBT is mediocre, dropping down to just 75.4% with the unit operating at 5% capacity.

Sirfa's design does keep the fan running after the PSU has been shut down, but it has no "semi-fanless" mode for when the PSU is operating, meaning that the fan starts as soon as the PSU has been turned on. In room temperature, the speed of the fan increases almost linearly with the load, reaching clearly audible levels with a load of about 600 Watts and a maximum of 42.5 dB(A) at full capacity.