Load Regulation, Hold-Up Time, Inrush Current, Efficiency and Noise
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EVGA SuperNOVA 750 G5
Corsair RM750
Corsair RM750x V2
Primary Rails And 5VSB Load Regulation
The following charts show the main rails' voltage values recorded between a range of 40W up to the PSU's maximum specified load, along with the deviation (in percent). Tight regulation is an important consideration every time we review a power supply because it facilitates constant voltage levels despite varying loads. Tight load regulation also, among other factors, improves the system’s stability, especially under overclocked conditions and, at the same time, it applies less stress to the DC-DC converters that many system components utilize.
The load regulation is tight on all rails. Unfortunately, we don't have data for the 750 G3 to make comparisons.
Hold-Up Time
Put simply; hold-up time is the amount of time that the system can continue to run without shutting down or rebooting during a power interruption.
The hold-up time is long and the power ok signal is accurate.
Inrush Current
Inrush current, or switch-on surge, refers to the maximum, instantaneous input current drawn by an electrical device when it is first turned on. A large enough inrush current can cause circuit breakers and fuses to trip. It can also damage switches, relays, and bridge rectifiers. As a result, the lower the inrush current of a PSU right as it is turned on, the better.
The inrush current is low with both voltage inputs.
10-110% Load Tests
These tests reveal the G5’s load regulation and efficiency levels under high ambient temperatures. They also show how the fan speed profile behaves under increased operating temperatures.
| Test # | 12V | 5V | 3.3V | 5VSB | DC/AC (Watts) | Efficiency | Fan Speed (RPM) | PSU Noise (dB[A]) | Temps (In/Out) | PF/AC Volts |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 4.384A | 2.026A | 1.993A | 1.018A | 74.581 | 84.032% | 0 | <6.0 | 45.19°C | 0.966 |
| 12.085V | 4.936V | 3.311V | 4.913V | 88.753 | 40.29°C | 115.15V | ||||
| 2 | 9.812A | 3.042A | 2.990A | 1.223A | 149.434 | 88.737% | 0 | <6.0 | 46.38°C | 0.988 |
| 12.080V | 4.934V | 3.309V | 4.908V | 168.401 | 41.08°C | 115.15V | ||||
| 3 | 15.648A | 3.548A | 3.477A | 1.429A | 224.971 | 90.185% | 0 | <6.0 | 47.09°C | 0.993 |
| 12.076V | 4.933V | 3.307V | 4.902V | 249.455 | 41.49°C | 115.15V | ||||
| 4 | 21.418A | 4.060A | 3.993A | 1.636A | 299.743 | 90.356% | 1379 | 37.5 | 41.78°C | 0.997 |
| 12.071V | 4.927V | 3.306V | 4.892V | 331.737 | 48.33°C | 115.16V | ||||
| 5 | 26.864A | 5.080A | 4.994A | 1.843A | 374.686 | 90.407% | 1481 | 40.2 | 42.03°C | 0.999 |
| 12.067V | 4.924V | 3.304V | 4.886V | 414.442 | 49.27°C | 115.16V | ||||
| 6 | 32.315A | 6.097A | 5.997A | 2.049A | 449.630 | 90.102% | 1670 | 42.6 | 42.88°C | 0.999 |
| 12.063V | 4.922V | 3.302V | 4.881V | 499.025 | 50.75°C | 115.16V | ||||
| 7 | 37.800A | 7.117A | 7.001A | 2.257A | 524.955 | 89.649% | 1773 | 46.1 | 43.23°C | 0.999 |
| 12.059V | 4.920V | 3.300V | 4.876V | 585.570 | 51.67°C | 115.16V | ||||
| 8 | 43.294A | 8.137A | 8.008A | 2.465A | 600.283 | 89.053% | 1882 | 46.2 | 43.80°C | 0.999 |
| 12.054V | 4.917V | 3.297V | 4.870V | 674.074 | 52.45°C | 115.16V | ||||
| 9 | 49.150A | 8.648A | 8.496A | 2.464A | 674.816 | 88.359% | 1930 | 47.9 | 44.66°C | 0.999 |
| 12.051V | 4.915V | 3.296V | 4.871V | 763.723 | 53.67°C | 115.17V | ||||
| 10 | 54.808A | 9.159A | 9.017A | 3.095A | 750.044 | 87.460% | 1935 | 48.8 | 45.89°C | 0.999 |
| 12.048V | 4.914V | 3.294V | 4.849V | 857.587 | 55.14°C | 115.18V | ||||
| 11 | 61.074A | 9.161A | 9.020A | 3.095A | 825.282 | 86.681% | 1937 | 48.9 | 46.67°C | 0.999 |
| 12.044V | 4.913V | 3.292V | 4.848V | 952.094 | 56.52°C | 115.17V | ||||
| CL1 | 0.155A | 14.001A | 14.001A | 0.000A | 117.073 | 80.557% | 0 | <6.0 | 49.25°C | 0.984 |
| 12.082V | 4.933V | 3.295V | 5.004V | 145.329 | 41.76°C | 115.17V | ||||
| CL2 | 62.528A | 1.004A | 1.001A | 1.000A | 766.544 | 87.976% | 1935 | 48.8 | 45.96°C | 0.999 |
| 12.049V | 4.923V | 3.299V | 4.899V | 871.306 | 55.53°C | 115.17V |
What makes an impression here is that during the CL1 test, the fan stops to spin, because of the low load, although the operating temperature is close to 42 degrees Celsius. Normally, the fan should spin at low RPM, to cool down the PSU's internals.
The 750 G5 easily meets the corresponding 80 PLUS Gold requirements, even at high ambient temperatures.
20-80W Load Tests
In the following tests, we measure the G5's efficiency at loads significantly lower than 10% of its maximum capacity (the lowest load the 80 PLUS standard measures). This is important for representing when a PC is idle with power-saving features turned on.
| Test # | 12V | 5V | 3.3V | 5VSB | DC/AC (Watts) | Efficiency | Fan Speed (RPM) | PSU Noise (dB[A]) | PF/AC Volts |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 1.203A | 0.508A | 0.480A | 0.203A | 19.641 | 67.551% | 0 | <6.0 | 0.881 |
| 12.088V | 4.937V | 3.313V | 4.934V | 29.076 | 115.16V | ||||
| 2 | 2.463A | 1.012A | 0.996A | 0.406A | 40.065 | 78.287% | 0 | <6.0 | 0.935 |
| 12.087V | 4.936V | 3.312V | 4.929V | 51.177 | 115.16V | ||||
| 3 | 3.651A | 1.520A | 1.479A | 0.609A | 59.520 | 82.740% | 0 | <6.0 | 0.955 |
| 12.085V | 4.935V | 3.311V | 4.925V | 71.936 | 115.15V | ||||
| 4 | 4.908A | 2.027A | 1.992A | 0.813A | 79.911 | 84.868% | 0 | <6.0 | 0.969 |
| 12.085V | 4.935V | 3.311V | 4.920V | 94.159 | 115.15V |
The efficiency with light loads is low.
2% or 10W Load Test
Intel plans on raising the ante at efficiency levels under ultra-light loads. So from July 2020, the ATX spec will require 70% and higher efficiency with 115V input. The applied load is only 10W for PSUs with 500W and lower capacities, while for stronger units we dial 2% of their max-rated-capacity.
| Test # | 12V | 5V | 3.3V | 5VSB | DC/AC (Watts) | Efficiency | Fan Speed (RPM) | PSU Noise (dB[A]) | PF/AC Volts |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 1.069A | 0.245A | 0.243A | 0.051A | 15.187 | 62.635% | 0 | <6.0 | 0.687 |
| 12.087V | 4.932V | 3.313V | 4.933V | 24.247 | 115.16V |
EVGA states that this unit is compatible with the ATX v2.52 specification, however from July 2020 the same spec will ask for at least 70% efficiency under such light load levels.
Efficiency
Next, we plotted a chart showing the G5’s efficiency at low loads, and loads from 10 to 110% of its maximum-rated capacity. The higher a PSU’s efficiency, the less energy goes wasted, leading to a reduced carbon footprint and lower electricity bills.
With normal loads the unit's efficiency is satisfactory, but this is not the case with light and super-light loads.
5VSB Efficiency
| Test # | 5VSB | DC/AC (Watts) | Efficiency | PF/AC Volts |
|---|---|---|---|---|
| 1 | 0.100A | 0.512 | 67.546% | 0.074 |
| 5.123V | 0.758 | 115.14V | ||
| 2 | 0.250A | 1.279 | 76.040% | 0.153 |
| 5.118V | 1.682 | 115.14V | ||
| 3 | 0.550A | 2.809 | 78.093% | 0.273 |
| 5.107V | 3.597 | 115.13V | ||
| 4 | 1.000A | 5.093 | 77.260% | 0.376 |
| 5.092V | 6.592 | 115.13V | ||
| 5 | 1.500A | 7.615 | 78.887% | 0.429 |
| 5.076V | 9.653 | 115.14V | ||
| 6 | 3.000A | 15.077 | 76.580% | 0.503 |
| 5.026V | 19.688 | 115.13V |
The 5VSB is has low efficiency, especially with 230V input.
Power Consumption In Idle And Standby
| Mode | 12V | 5V | 3.3V | 5VSB | Watts | PF/AC Volts |
|---|---|---|---|---|---|---|
| Idle | 12.087V | 4.928V | 3.313V | 4.929V | 8.148 | 0.458 |
| 115.2V | ||||||
| Standby | 0.172 | 0.017 | ||||
| 115.2V | ||||||
The vampire power exceeds 0.25W and this is why the 750 G5 cannot meet the requirements even of the lowest Cybenetics efficiency rating. It is a shame to see such high energy consumption at standby, in a modern PSU.
Fan RPM, Delta Temperature, And Output Noise
All results are obtained between an ambient temperature of 37 to 47 degrees Celsius (98.6 to 116.6 degrees Fahrenheit).
The fan profile is super aggressive when the power supply is pushed hard, under high temperatures.
The following results were obtained at 30 to 32 degrees Celsius (86 to 89.6 degrees Fahrenheit) ambient temperature.
The passive operation lasts for quite long, but afterward, the fan quickly increases its speed, and with higher than 525W loads, the noise output exceeds 40 dB(A).
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