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Phanteks AMP Series 550W Power Supply Review

(Image: © Tom's Hardware)

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.

The load regulation is tight 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.

The hold-up time exceeds 17ms, and the power ok signal is accurate, but lower than 16ms as the ATX spec requires. 

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 currents are at normal levels. 

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.

Test #12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed (RPM)PSU Noise (dB[A])Temps (In/Out)PF/AC Volts
12.722A2.003A1.989A0.982A54.53883.328%0<6.0 45.81°C0.917
12.097V4.997V3.319V5.092V65.450 40.54°C115.12V
26.492A3.004A2.986A1.181A109.44988.172%0<6.0 46.94°C0.954
12.098V4.994V3.317V5.083V124.131 40.85°C115.12V
310.656A3.506A3.469A1.380A164.94189.534%0<6.0 47.62°C0.969
12.100V4.992V3.315V5.074V184.221 41.15°C115.12V
414.753A4.009A3.984A1.580A219.75589.694%0<6.0 48.64°C0.978
12.102V4.991V3.314V5.065V245.004 41.89°C115.12V
518.519A5.011A4.982A1.781A274.64989.573%5608.5 42.67°C0.983
12.103V4.991V3.312V5.055V306.619 49.88°C115.12V
622.286A6.016A5.982A1.983A329.56689.190%5718.5 43.11°C0.984
12.104V4.989V3.310V5.044V369.509 50.90°C115.11V
726.087A7.019A6.982A2.185A384.86688.719%68511.0 43.38°C0.986
12.104V4.987V3.309V5.035V433.804 51.57°C115.11V
829.886A8.027A7.984A2.389A440.16988.067%100320.8 43.90°C0.988
12.104V4.986V3.307V5.024V499.812 52.76°C115.11V
934.057A8.529A8.473A2.392A494.68387.488%134030.2 45.17°C0.989
12.102V4.985V3.305V5.019V565.431 54.61°C115.11V
1038.033A9.033A8.990A3.000A549.88486.702%175333.2 45.31°C0.989
12.099V4.984V3.304V5.000V634.222 56.05°C115.11V
1142.601A9.033A8.991A3.003A605.10785.968%209841.1 46.57°C0.990
12.098V4.984V3.303V4.996V703.877 58.17°C115.11V
CL10.142A12.002A12.001A0.000A101.24885.136%0 <6.0 49.34°C0.952
12.107V4.984V3.309V5.100V118.925 42.48°C115.12V
CL245.005A1.002A0.999A1.000A557.83987.464%1609 33.1 45.54°C0.989
12.098V4.994V3.311V5.057V637.796 55.97°C115.11V

Up to the 40% load test, the PSU operates in passive mode, despite the high ambient temperatures. Afterward, the fan kicks in at low speeds. It needs more than full load at almost 47 degrees Celsius, to force the fan spin at full speed, where the noise output exceeds 40 dB(A).

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.

Test #12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed (RPM)PSU Noise (dB[A])PF/AC Volts

The fan doesn't need to spin at such light loads, even at higher than 35 degrees Celsius ambient temperatures. 

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 #12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed (RPM)PSU Noise (dB[A])PF/AC Volts

The efficiency with 2% load is low. 


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 efficiency levels could be higher in all segments (super light, light, and normal loads). 

5VSB Efficiency

Test #5VSBDC/AC (Watts)EfficiencyPF/AC Volts

The 5VSB rail's efficiency levels cannot meet the competition. 

Power Consumption In Idle And Standby

Mode12V5V3.3V5VSBWattsPF/AC Volts

The energy that the PSU consumes in standby mode is 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).

(Image credit: Tom's Hardware)

(Image credit: Tom's Hardware)

The fan profile at high operating temperatures is not aggressive since it takes more than full load at close to 47 degrees Celsius to make the fan spin at its full speed. 

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

(Image credit: Tom's Hardware)

(Image credit: Tom's Hardware)

The passive operation lasts long, and up to around 360W loads, the PSU is dead silent. With higher than 440W loads, at +12V, the fan's noise enters the 35-40 dB(A) range. 

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MORE: How We Test Power Supplies

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Aris Mpitziopoulos
Contributing Editor

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