EVGA SuperNOVA 850 G7 Power Supply Review

To learn more about our PSU tests and methodology, please check out How We Test Power Supply Units. 

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. At the same time, it applies less stress to the DC-DC converters that many system components utilize.

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Load regulation is satisfactory on all rails. 

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.

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The hold-up time is long and the power ok signal is accurate. The "PWR OK Inactive to DC Loss Delay" signal could be shorter, though. 

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.

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Inrush current is high with both voltage inputs, 115V and 230V, that we tried. 

Leakage Current

In layman's terms, leakage current is the unwanted transfer of energy from one circuit to another. In power supplies, it is the current flowing from the primary side to the ground or the chassis, which in the majority of cases is connected to the ground. For measuring leakage current, we use a GW Instek GPT-9904 electrical safety tester instrument.

The leakage current test is conducted at 110% of the DUT's rated voltage input (so for a 230-240V device, we should conduct the test with 253-264V input). The maximum acceptable limit of a leakage current is 3.5 mA and it is defined by the IEC-60950-1 regulation, ensuring that the current is low and will not harm any person coming in contact with the power supply's chassis.

Leakage current is low. 

10-110% Load Tests

These tests reveal the PSU's load regulation and efficiency levels under high ambient temperatures. They also show how the fan speed profile behaves under increased operating temperatures.

The PSU can handle harsh operating conditions, that is, increased loads and temperatures, but don't expect it to be quiet. 

20-80W Load Tests

In the following tests, we measure the PSU'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.

The unit achieves high efficiency under light loads, with minimal noise output because the fan doesn't spin. 

2% or 10W Load Test

From July 2020, the ATX spec requires 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.

The PSU exceeds 60% efficiency with a 2% load. It would be nice to measure above 70%, though, in this test scenario. 

Efficiency & Power Factor

Next, we plotted a chart showing the PSU'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. The same goes for Power Factor.

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The platform is highly efficient with normal loads, also achieving good results with light loads. The competition is tough at light and super-light loads, so FSP could improve the platform in these sectors. 

5VSB Efficiency

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The 5VSB rail is efficient. 

Power Consumption In Idle And Standby

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We would like to see below 0.1W vampire power with 230V input. 

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's speed is not aggressive considering the test conditions, the tiny and overpopulated PCB, and the high power output. 

The following results were obtained at 30 to 32 degrees Celsius (86 to 89.6 degrees Fahrenheit) ambient temperature.       

Some spots in the PSU's noise map at normal operating temperatures indicate that the fan speed increased notably to cope with heat build-up. This is why it is preferable to have the fan spinning at all times rather than employing a semi-passive operation mode. With more than 690W, the PSU exceeds 30 dBA; with 20-30W more, it goes over 35 dBA. With a larger PCB, allowing for more airflow between parts, and a 135-140mm fan, things could be better in noise output. 

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