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Fractal Design Ion SFX Gold 500W Power Supply Review

Top performance at a reasonable price.

Editor's Choice
(Image: © Tom's Hardware)

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


Advanced Transient Response at 20% – 20ms


Advanced Transient Response at 20% – 1ms


Advanced Transient Response at 50% – 200ms


Advanced Transient Response at 50% – 20ms


Advanced Transient Response at 50% – 1ms


The transient response is good, overall. Only in the 3.3V rail, the Ion SFX model doesn't reach the top performance of Corsair's SFX offerings, but this rail is not so important anymore.

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.

There is a small voltage overshoot at 5VSB, while the +12V rail has a less linear slope, which won't be the cause of any trouble, 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.

LoadT1 (Power-on time)T3 (PWR_OK delay)

The PWR_OK delay is out of the 100-150ms region, so the PSU does not support the alternative sleep mode, which will be a requirement, according to our sources at least, by the ATX v2.52 from 2020.

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).

10% Load15.5 mV6.0 mV14.3 mV11.4 mVPass
20% Load17.5 mV6.4 mV14.4 mV10.8 mVPass
30% Load15.5 mV6.6 mV13.4 mV11.1 mVPass
40% Load14.6 mV6.9 mV13.8 mV11.0 mVPass
50% Load14.4 mV7.1 mV13.9 mV11.5 mVPass
60% Load15.2 mV7.5 mV14.6 mV11.5 mVPass
70% Load15.9 mV8.3 mV15.4 mV11.7 mVPass
80% Load16.5 mV8.1 mV16.8 mV12.7 mVPass
90% Load17.0 mV9.0 mV16.9 mV13.1 mVPass
100% Load25.6 mV10.0 mV20.3 mV15.3 mVPass
110% Load25.9 mV10.0 mV17.8 mV16.4 mVPass
Crossload 123.6 mV9.7 mV19.0 mV13.0 mVPass
Crossload 225.5 mV7.8 mV16.6 mV15.1 mVPass

The ripple suppression is good on all voltage rails. 

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)

We measured higher than the limits EMI spikes at 150KHz and 150KHz. In the rest frequency range the conducted EMI emissions are much lower than the corresponding limits. 

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Aris Mpitziopoulos
Contributing Editor

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