Corsair HX750i Power Supply Review

Cold Test Results

For testing PSUs, we use 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.

Honoring its 80 Plus Platinum certification, the Corsair HX750i displays outstanding performance at room temperature. The peak efficiency is 94.3% at 50% load and the average within the nominal load range (20% to 100% of the unit's capacity) is an astonishing 92.9%. The HX750i performs well under low loads as well, with the efficiency plummeting only when the load is less than 50 Watts.

The very high efficiency of the HX750i combined with the hybrid fan design allows the HX750i to operate with its fan turned off with a load up to about 300 Watts. After that, the fan will start but the power supply will remain essentially quiet with a load up to 600 Watts. Only when the load exceeds that point does the fan becomes clearly audible, yet it never reaches the point where we would consider it loud -- especially if it's housed in a closed case.