Load Regulation, Hold-Up Time And Inrush Current
To learn more about our PSU tests and methodology, please check out How We Test Power Supply Units.
Primary Rails And 5VSB Load Regulation
Load Regulation testing is detailed here.
Our hold-up time tests are described in detail here.
The hold-up time was pretty long, which we expected from the increased combined capacity of the bulk caps.
For details on our inrush current testing, please click here.
The inrush current is at normal levels for a 750 W PSU equipped with two large bulk caps.
Load Regulation And Efficiency Measurements
The first set of tests reveals the stability of the voltage rails and the PSU's efficiency. The applied load equals (approximately) 10 to 110 percent of the maximum load the supply can handle, in increments of 10 percentage points.
We conducted two additional tests. During the first, we stressed the two minor rails (5V and 3.3V) with a high load, while the load at +12V was only 0.10A. This test reveals whether a PSU is Haswell-ready or not. In the second test, we determined the maximum load the +12V rail could handle with minimal load on the minor rails.
|Test||12V||5V||3.3V||5VSB||Power(DC/AC)||Efficiency||Fan Speed||Fan Noise||Temp(In/Out)||PF/AC Volts|
|10% Load||4.392A||2.002A||1.980A||1.002A||74.76W||84.63%||0 RPM||0 dB(A)||47.44 °C||0.968|
|20% Load||9.833A||3.000A||2.972A||1.205A||149.76W||88.86%||0 RPM||0 dB(A)||48.34 °C||0.989|
|30% Load||15.635A||3.507A||3.485A||1.405A||224.88W||90.10%||0 RPM||0 dB(A)||49.87 °C||0.993|
|40% Load||21.438A||4.004A||3.967A||1.610A||299.72W||90.40%||0 RPM||0 dB(A)||51.39 °C||0.995|
|50% Load||26.919A||4.999A||4.963A||1.810A||374.67W||90.23%||0 RPM||0 dB(A)||53.71 °C||0.996|
|60% Load||32.413A||6.013A||5.958A||2.015A||449.64W||89.77%||488 RPM||22.4 dB(A)||41.97 °C||0.997|
|70% Load||37.919A||7.014A||6.959A||2.220A||524.59W||89.21%||608 RPM||25.3 dB(A)||43.34 °C||0.997|
|80% Load||43.446A||8.022A||7.957A||2.423A||599.56W||88.63%||744 RPM||29.7 dB(A)||44.85 °C||0.997|
|90% Load||49.424A||8.522A||8.474A||2.424A||674.61W||87.90%||848 RPM||32.6 dB(A)||45.17 °C||0.997|
|100% Load||55.153A||9.035A||8.959A||3.040A||749.45W||87.06%||944 RPM||34.4 dB(A)||46.42 °C||0.997|
|110% Load||61.504A||9.039A||8.963A||3.040A||824.37W||86.23%||1200 RPM||41.0 dB(A)||47.48 °C||0.997|
|Cross-Load 1||0.098A||18.022A||18.003A||0.004A||150.94W||81.48%||688 RPM||26.9 dB(A)||46.23 °C||0.991|
|Cross-Load 2||62.448A||1.002A||1.003A||1.002A||760.38W||87.50%||960 RPM||34.6 dB(A)||48.46 °C||0.997|
Load regulation on the +12V rail was good, although we would like to see a reading within 1 percent. On the rest of the rails regulation was much tighter, with the 5V and 3.3V rails easily staying well below 1 percent. In addition, efficiency easily met the 80 Plus Gold requirements with 20 percent and 50 percent load; however, with a full load it was very close to the lower allowed level. As a reminder, the 80 Plus organization conducts the certification tests at only 23 C (73.4 F), while we test at a much higher ambient temperature, so it is natural to measure significantly lower efficiency throughout all load ranges.
In the noise output section, the RM750i carries on the tradition of the RM line with its silent operation, even under extremely tough conditions. Up to the 50 percent load test, the PSU operated in fanless mode, and even when the fan engaged it did so at very low speeds and we had to actually overload the PSU to make the fan's speed exceed 1000 RPM. This is the most silent 750 W we have ever tested and we are pretty sure that this alone will be a key buying factor for many users.
Corsair Link Screenshots
You will find several screenshots of the Corsair Link software below, which we took during our test sessions.