Fractal Design Ion SFX Gold 500W Power Supply Review

Top performance at a reasonable price.

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(Image: © Tom's Hardware)

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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 is much longer than what the ATX spec requires (17ms). Moreover, the power ok signal 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.

The inrush current is 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.

Swipe to scroll horizontally
Test #12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed (RPM)PSU Noise (dB[A])Temps (In/Out)PF/AC Volts
12.346A1.978A1.974A0.977A49.75383.262%0<6.0 44.94°C0.935
11.994V5.060V3.345V5.121V59.755 40.24°C115.18V
25.744A2.969A2.963A1.174A99.85487.955%0<6.0 45.63°C0.973
12.002V5.056V3.342V5.112V113.529 40.50°C115.17V
39.475A3.465A3.441A1.372A149.74688.980%89320.7 41.02°C0.981
12.005V5.052V3.340V5.103V168.291 46.67°C115.17V
413.209A3.964A3.956A1.571A199.77389.580%90320.9 41.57°C0.982
12.004V5.048V3.337V5.093V223.010 47.59°C115.17V
516.606A4.958A4.947A1.771A249.86989.513%97723.2 42.16°C0.985
12.005V5.045V3.335V5.084V279.144 48.45°C115.16V
620.002A5.952A5.940A1.972A299.95089.011%134932.5 42.77°C0.984
12.006V5.041V3.333V5.073V336.981 49.73°C115.16V
723.401A6.949A6.934A2.173A350.08388.469%166739.0 43.27°C0.983
12.007V5.038V3.331V5.063V395.713 51.22°C115.16V
826.796A7.946A7.930A2.376A400.20387.883%186342.3 43.72°C0.983
12.009V5.035V3.329V5.052V455.381 52.70°C115.15V
930.591A8.448A8.416A2.379A449.91187.454%200944.4 44.73°C0.984
12.010V5.032V3.327V5.045V514.457 54.10°C115.14V
1034.153A8.950A8.933A2.983A499.92586.859%207046.4 45.11°C0.986
12.011V5.029V3.325V5.029V575.557 55.25°C115.14V
1138.308A8.953A8.935A2.987A549.95286.293%208246.7 46.20°C0.987
12.014V5.028V3.324V5.023V637.309 56.84°C115.14V
CL10.150A12.001A12.001A0.000A102.20383.351%1260 31.4 43.82°C0.974
12.016V5.036V3.330V5.112V122.617 50.54°C115.17V
CL241.016A1.005A1.000A1.000A506.16887.795%2079 46.6 45.21°C0.986
12.012V5.047V3.338V5.074V576.532 55.63°C115.13V

During the first two tests, the PSU's fan is inactive, while afterward, it starts spinning at low speeds till the sixth test. The unit's efficiency is satisfactory, despite the high operating temperatures. Still, the APFC converter's performance could be improved since, even at high loads, the PF readings are not as close to unity as in other, similar spec products.

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.

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

The fan doesn't spin, at all, at light loads, even at high operating 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.

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

The PSU's efficiency isn't even close to 70%, which is what the ATX spec will require, according to our sources, at least, from 2020.


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 with light (20-80W) loads is fine, but this doesn't look to be the case with normal loads (10-100% of the PSU's max-rated capacity).

5VSB Efficiency

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

The 5VSB rail's efficiency is not high enough to meet the Corsair competition. 

Power Consumption In Idle and Standby

Swipe to scroll horizontally
Mode12V5V3.3V5VSBWattsPF/AC Volts
StandbyRow 3 - Cell 1 Row 3 - Cell 2 Row 3 - Cell 3 Row 3 - Cell 4 0.0450.008
Row 4 - Cell 0 Row 4 - Cell 1 Row 4 - Cell 2 Row 4 - Cell 3 Row 4 - Cell 4 115.21V

The vampire lower 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 is not as aggressive as it is in the 650W Ion SFX model.

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 operating range has a weird shape, and it is not as large as we expected. With more than 330W load the PSU's fan exceeds 30 db(A) and with more than 375W it enters the 35-40 dB(A) range. The fan profile could be more relaxed, but Seasonic's engineers also had to make sure that the PSU will outlive the extra-long warranty.

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Aris Mpitziopoulos
Contributing Editor

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