Phanteks AMP Series 750W 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 and, at the same time, it applies less stress to the DC-DC converters that many system components utilize.

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Results 1-8: Load Regulation

The load regulation is extra-tight on all rails but 5VSB, where it is satisfactory. 

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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Results 9-12: Hold-Up Time

The hold-up time is close to 20ms while the power-ok signal exceeds the threshold that the ATX spec sets, and it 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.

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Results 13-14: Inrush Current

The inrush currents are a bit higher than the competition's. 

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 power supply operates in passive mode, up to the 20% load test. The fan starts at low RPM, in the 30% test, and the noise output remains low until the 50% load test. Finally, the PSU doesn't have a problem delivering more than its full load at temperatures close to 47 degrees Celsius, where the fan operates at its full speed. 

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.

With 20% load we would like to see over 70% efficiency. In the other three tests the efficiency levels are satisfactory but not among the highest we have seen so far. 

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.

The efficiency with a 2% load of the PSU's max-rated-capacity should exceed 70%. 

Efficiency

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.

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Results 15-18: Efficiency

With normal loads, the efficiency levels are not so high, while with light loads, the PSU performs better. Finally, with a 2% load, the efficiency doesn't even get close to 70%, which is what the ATX spec will require from July 2020. 

5VSB Efficiency

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Results 19-20: 5VSB Efficiency

The 5VSB rail needs an upgrade, to become more efficient. 

Power Consumption In Idle And Standby

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Results 21-22: Vampire Power

The vampire power levels are low, with both voltage inputs. 

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, at high operating temperatures, is aggressive. The semi-passive mode doesn't last long, and with 525W and higher loads, the fan's noise output exceeds 40 dB(A).

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

At normal temperatures, for a chassis' internals, the fan speed profile remains aggressive, and the 40 dB(A) mark breaks with 600W and higher loads. 

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