Corsair HX750i Power Supply Review

Hot Test Results

As the numbers in the following tables depict, the Corsair HX750i offers great power quality and maintains its superb electrical performance when subjected to high ambient temperatures. Our instrumentation recorded a maximum ripple of 40mV on the 12V line, a very good performance figure and slightly better than that of the RM1000 under the same load, despite the fact that both units are based on essentially the same platform. The voltage regulation is excellent, with the 12V line staying within 1.4% and the 3.3V/5V lines within just 1.2%.

High ambient temperatures do have a negative impact on the electrical performance of the HX750i, but that impact is relatively small for a 750W PSU. The average nominal load (20-100%) efficiency drops by 0.3% and the maximum efficiency goes down to 94.0% at 50% load. Even though just barely, the Corsair HX750i could maintain its 80 Plus Platinum certification during this test as well, with an ambient temperature over 20°C higher than that of the 80 Plus testing requirements.

Strangely, even with a high ambient temperature, the fan of the Corsair HX750i starts at exactly the same point, meaning that the PSU will operate fanless with a load lower than 300 Watts regardless of the ambient conditions. Once the fan starts however, its speed will increase faster than in the previous test, making the HX750i noticeable with a load of 450 Watts, but the PSU still generates very little noise for a 750W unit even under maximum stress, with a maximum noise level of just under 42 dB(A).