Fractal Design Ion SFX Gold 650W Power Supply Review

Great performance, highly modular.

(Image: © Fractal Design)

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.

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 is much longer than the required (17ms), and 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 high, with 230V input. 

10-110% Load Tests

These tests reveal the Ion'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
13.634A1.971A1.972A0.977A64.93684.89%8762040.09 C0.927
.11.920V5.077V3.351V5.121V76.491...44.57 C115.12V
28.268A2.959A2.961A1.174A129.45388.31%89620.840.43 C0.952
.11.918V5.071V3.346V5.113V146.59...45.25 C115.12V
313.306A3.454A3.441A1.371A194.55389.18%90721.541.06 C0.966
.11.915V5.069V3.343V5.105V218.164...46.20 C115.12V
418.341A3.949A3.951A1.570A259.74889.51%104826.441.22 C0.973
.11.915V5.068V3.341V5.097V290.196...47.03 C115.12V
523.048A4.937A4.940A1.769A325.09389.05%155137.142.81 C0.979
.11.913V5.067V3.341V5.089V365.052...49.14 C115.12V
627.691A5.926A5.931A1.969A389.59488.72%170440.542.92 C0.981
.11.909V5.065V3.339V5.080V439.149...50.01 C115.12V
732.398A6.913A6.923A2.169A454.88888.14%198043.643.56 C0.982
.11.907V5.065V3.338V5.072V516.089...51.24 C115.12V
837.106A7.902A7.912A2.371A520.20687.47%204445.844.19 C0.984
.11.906V5.064V3.337V5.063V594.759...52.45 C115.12V
942.213A8.397A8.394A2.373A585.10886.94%204945.944.27 C0.986
.11.906V5.063V3.336V5.058V673.021...53.19 C115.11V
1047.058A8.891A8.906A2.975A649.94686.19%205646.245.71 C0.988
.11.905V5.063V3.335V5.043V754.113...54.90 C115.12V
1152.503A8.891A8.904A2.978A714.77485.47%205546.246.54 C0.99
.11.905V5.063V3.336V5.039V836.325...56.25 C115.11V
CL10.148A12.003A12.000A0.000A102.68783.00%145735.542.96 C0.946
.11.927V5.066V3.343V5.125V123.727...49.60 C115.13V
CL254.021A1.003A1.001A1.000A656.52986.85%205846.245.51 C0.988
.11.903V5.073V3.343V5.082V755.914...54.84 C115.12V

Up to the 40% load test, the fan spins at average speeds, given the load and temperature conditions, but afterward, its speed skyrockets, affecting notably the noise output. 

The APFC converter needs a slight tuning since the power factor readings are not that high even under high loads. 

20-80W Load Tests

In the following tests, we measure the Ion'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.

Swipe to scroll horizontally
Test #12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed (RPM)PSU Noise (dB[A])PF/AC Volts
11.222A0.493A0.476A0.195A19.66572.83%0 less than 6.00.815
22.496A0.983A0.985A0.390A40.04281.89%0 less than 6.00.896
33.705A1.478A1.461A0.585A59.55385.55%0 less than 6.00.921
44.979A1.970A1.970A0.781A79.94286.77%0 less than 6.00.932

Under light loads there is no need for the PSU's fan to spin.

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.

Swipe to scroll horizontally
Test #12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed (RPM)PSU Noise (dB[A])PF/AC Volts
10.932A0.205A0.203A0.051A13.06965.62%0less than 6.00.743


The efficiency with light loads exceeds 65%, so it is quite high. Nonetheless, the ATX spec will require higher than 70% in 2020. 

Next, we plotted a chart showing the Ion’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 normal loads is low, compared to the competing offerings. With light and super-light loads, the Ion model takes its revenge, though.  

5VSB Efficiency

Swipe to scroll horizontally
Test #5VSBDC/AC (Watts)EfficiencyPF/AC Volts

The 5VSB rail has low efficiency. 

Power Consumption In Idle And Standby

Swipe to scroll horizontally
Mode12V5V3.3V5VSBWattsPF/AC Volts

The vampire is low, something that helps the 5VSB rail's efficiency under light load. 

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 gets aggressive, under high operating temperatures.

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)

Even under normal operating temperatures, the fan profile gets aggressive with higher than 340W loads. 

MORE: Best Power Supplies

MORE: How We Test Power Supplies

MORE: All Power Supply Content

Aris Mpitziopoulos
Contributing Editor

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