EVGA SuperNOVA 850 P6 Power Supply Review

The EVGA SuperNOVA 850 P6 is a good PSU, but the 850 G6 is a better choice.

EVGA SuperNOVA 850 P6
(Image: © Tom's Hardware, Shutterstock)

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Advanced Transient Response Tests

For details about our transient response testing, please click here.

In the real world, power supplies are always working with loads that change. It's of immense importance, then, for the PSU to keep its rails within the ATX specification's defined ranges. The smaller the deviations, the more stable your PC will be with less stress applied to its components. 

We should note that the ATX spec requires capacitive loading during the transient rests, but in our methodology, we also choose to apply a worst case scenario with no additional capacitance on the rails. 

Advanced Transient Response at 20% – 20ms

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Advanced Transient Response at 20% – 10ms

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Advanced Transient Response at 20% – 1ms

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Advanced Transient Response at 50% – 20ms

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Advanced Transient Response at 50% – 10ms

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Advanced Transient Response at 50% – 1ms

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Transient response is not great, especially at 3.3V, where the PSU failed in several tests. 

Turn-On Transient Tests

In the next set of tests, we measure the PSU's response in simpler transient load scenarios—during its power-on phase. Ideally, we don't want to see any voltage overshoots or spikes since those put a lot of stress on the DC-DC converters of installed components.

We only found a small step at 5VSB, which is nothing to worry about. Both 12V slopes are fine. 

Power Supply Timing Tests

There are several signals generated by the power supply, which need to be within specified, by the ATX spec, ranges. If they are not, there can be compatibility issues with other system parts, especially mainboards. From year 2020, the PSU's Power-on time (T1) has to be lower than 150ms and the PWR_OK delay (T3) from 100 to 150ms, to be compatible with the Alternative Sleep Mode.

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PSU Timings Table
T1 (Power-on time) & T3 (PWR_OK delay)

The PWR_OK delay is within the 100-150ms region, so the PSU supports the alternative sleep mode recommended by the ATX spec.

Ripple Measurements

Ripple represents the AC fluctuations (periodic) and noise (random) found in the PSU's DC rails. This phenomenon significantly decreases the capacitors' lifespan because it causes them to run hotter. A 10-degree Celsius increase can cut into a cap's useful life by 50%. Ripple also plays an important role in overall system stability, especially when overclocking is involved.

The ripple limits, according to the ATX specification, are 120mV (+12V) and 50mV (5V, 3.3V, and 5VSB).

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10% Load9.0 mV10.2 mV12.5 mV7.1 mVPass
20% Load11.2 mV9.1 mV11.7 mV6.6 mVPass
30% Load11.4 mV9.6 mV11.8 mV7.3 mVPass
40% Load10.4 mV11.9 mV13.0 mV10.8 mVPass
50% Load10.2 mV11.3 mV12.3 mV12.1 mVPass
60% Load10.0 mV11.7 mV13.0 mV9.9 mVPass
70% Load10.6 mV11.8 mV13.8 mV16.3 mVPass
80% Load11.4 mV12.8 mV14.5 mV17.7 mVPass
90% Load11.3 mV12.5 mV15.0 mV13.3 mVPass
100% Load16.1 mV14.5 mV16.8 mV15.1 mVPass
110% Load16.1 mV17.6 mV19.1 mV15.8 mVPass
Crossload 19.1 mV11.4 mV14.5 mV7.5 mVPass
Crossload 28.9 mV10.9 mV11.7 mV6.4 mVPass
Crossload 38.9 mV9.4 mV13.8 mV6.2 mVPass
Crossload 416.0 mV13.2 mV16.1 mV16.3 mVPass

Ripple suppression is excellent on all rails. 

Ripple At Full Load

Ripple At 110% Load

Ripple At Cross-Load 1

Ripple At Cross-Load 4

EMC Pre-Compliance Testing – Average & Quasi-Peak EMI Detector Results

Electromagnetic Compatibility (EMC) is the ability of a device to operate properly in its environment without disrupting the proper operation of other nearby devices.

Electromagnetic Interference (EMI) stands for the electromagnetic energy a device emits, and it can cause problems in other nearby devices if too high. For example, it can be the cause of increased static noise in your headphones or/and speakers.

(Image credit: Tom's Hardware)

There are seven EMI spikes with the AVG detector, all within 338-855KHz. With the Peak EMI detector, everything went fine. 

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MORE: How We Test Power Supplies

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Contributing Editor

Aris Mpitziopoulos is a Contributing Editor at Tom's Hardware US, covering PSUs.

  • Co BIY
    Thanks - I've been asking for this review.

    Hard to beat the Corsair RMx 850 right now when it is shipping direct from them at $115.

    I think a discussion at the beginning of each review that hits on the right use case for the power supply would be helpful. Do I need a 850 Watt power supply ? Is there any advantage to going lower or is this supply just as efficient all the way down the ladder so that getting the optimum wattage isn't that important?