EVGA SuperNOVA 850 G7 Power Supply Review

The EVGA SuperNOVA 850 G7 is a super-compact, high-performance PSU.

EVGA SuperNOVA 850 G7
Editor's Choice
(Image: © Tom's Hardware)

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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 good at 12V, 3.3V and 5VSB and satisfactory at 5V. 

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 didn't notice any notable voltage overshoots or voltage spikes, in these tests. 

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% Load6.3 mV4.9 mV6.7 mV8.5 mVPass
20% Load7.5 mV5.3 mV6.7 mV10.0 mVPass
30% Load7.6 mV5.8 mV7.4 mV9.9 mVPass
40% Load8.0 mV6.7 mV7.4 mV9.3 mVPass
50% Load8.7 mV6.7 mV7.8 mV10.3 mVPass
60% Load9.3 mV7.2 mV8.8 mV12.1 mVPass
70% Load9.9 mV7.3 mV9.6 mV13.3 mVPass
80% Load10.8 mV8.1 mV9.7 mV13.5 mVPass
90% Load11.9 mV9.9 mV11.2 mV13.9 mVPass
100% Load18.6 mV10.4 mV11.9 mV16.3 mVPass
110% Load20.4 mV14.0 mV12.7 mV15.6 mVPass
Crossload 110.2 mV7.5 mV8.6 mV6.8 mVPass
Crossload 26.8 mV6.3 mV7.7 mV5.5 mVPass
Crossload 36.9 mV6.4 mV8.2 mV4.1 mVPass
Crossload 418.4 mV9.8 mV10.5 mV6.6 mVPass

Ripple suppression is good 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 and 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) is the electromagnetic energy a device emits, and it can cause problems in other nearby devices if too high. For example, it can cause increased static noise in your headphones or/and speakers.

΅We use TekBox's EMCview to conduct our EMC pre-compliance testing.

(Image credit: Tom's Hardware)

EMI emissions are low, with both the average and peak EMI detectors. 

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Aris Mpitziopoulos
Contributing Editor

Aris Mpitziopoulos is a contributing editor at Tom's Hardware, covering PSUs.

  • Co BIY
    Thanks for the review!

    Glad to see a new leader. EVGA is back in it.

    I think a short description of what level of system would be well served/matched to a power supply of this wattage would be a great addition to the review format.

    Something along the lines of : A well performing 850 Watt PSU like this one is well suited to power a gaming system up to an i5 12600K (150 watt TDP) with an RTX 3070 Ti GPU (290 Watt). -