Phanteks AMP Series 550W Power Supply Review

(Image: © Tom's Hardware)

Why you can trust Tom's Hardware Our expert reviewers spend hours testing and comparing products and services so you can choose the best for you. Find out more about how we test.

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% – 200ms

Swipe to scroll horizontally

Advanced Transient Response at 20% – 20ms

Swipe to scroll horizontally

Advanced Transient Response at 20% – 1ms

Swipe to scroll horizontally

Advanced Transient Response at 50% – 200ms

Swipe to scroll horizontally

Advanced Transient Response at 50% – 20ms

Swipe to scroll horizontally

Advanced Transient Response at 50% – 1ms

Swipe to scroll horizontally

The transient response at +12V, which is the most crucial rail, is good. The voltage deviations are high on the minor rails, though, especially at 3.3V. 

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.

The voltage at +12V takes some time to reach the nominal value. This won't create any problems, though. 

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.

Swipe to scroll horizontally
T1 (Power-on time) & T3 (PWR_OK delay)Row 0 - Cell 1 Row 0 - Cell 2

The PWR_OK delay is out of the 100-150ms region, so according to the ATX spec, the PSU does not meet the requirements of the alternative sleep mode.

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).

Swipe to scroll horizontally
10% Load12.0 mV10.3 mV6.8 mV5.5 mVPass
20% Load16.9 mV12.9 mV8.6 mV5.7 mVPass
30% Load20.0 mV12.9 mV9.6 mV5.9 mVPass
40% Load22.5 mV12.9 mV10.1 mV5.9 mVPass
50% Load24.4 mV14.2 mV10.5 mV6.3 mVPass
60% Load25.9 mV15.2 mV11.0 mV7.2 mVPass
70% Load27.6 mV16.8 mV11.0 mV6.7 mVPass
80% Load28.7 mV17.7 mV13.7 mV8.5 mVPass
90% Load29.6 mV21.1 mV14.3 mV9.1 mVPass
100% Load31.1 mV24.3 mV15.5 mV8.4 mVPass
110% Load33.3 mV24.8 mV16.4 mV9.5 mVPass
Crossload 116.0 mV17.7 mV11.8 mV5.4 mVPass
Crossload 230.6 mV16.3 mV13.9 mV7.6 mVPass

The lack of in-cable capacitors doesn't allow for flawless ripple suppression. Nonetheless, the PSU achieves satisfactory performance in this section.

Ripple At Full Load

Ripple At 110% Load

Ripple At Cross-Load 1

Ripple At Cross-Load 2

EMC Pre-Compliance Testing – Average & 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 close-by devices.

Electromagnetic Interference (EMI) stands for the electromagnetic energy a device emits, and it can cause problems in other close-by 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 no high spurs, that exceed the corresponding limits. 

MORE: Best Power Supplies

MORE: How We Test Power Supplies

MORE: All Power Supply Content

Contributing Editor

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