Fractal Design Ion SFX Gold 650W Power Supply Review

Great performance, highly modular.

(Image: © Fractal Design)

Tom's Hardware Verdict

Fractal Design's Ion SFX model with 650W max power offers high performance, highly flexible modular cables and compact dimensions at a reasonable price.


  • +

    SFX-to-ATX mounting bracket

  • +

    Flexible and fully modular cables

  • +

    Ten-year warranty


  • -

    Could be quieter

  • -

    Efficiency could be higher

  • -

    Low 5VSB efficiency

  • -

    High inrush current with 230V input

  • -

    Some high EMI peaks at low frequencies

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The Ion SFX 650G is an excellent SFX power supply, able to match the quality of the  Corsair SF600, which still leads the 600W SFX category with Cybenetics ETA-A and 80 PLUS Gold efficiency certifications. The added benefits of the Ion model over the similar capacity Corsair SFX model are the larger fan, which is driven by a rather aggressive speed profile though, the ten-year warranty, the highly flexible modular cables, and the ATX-to-SFX adapter bracket which is missing in the SF600 Gold unit's bundle. Besides Corsair's offering, worthy opponents of the Ion 650G are the EVGA 650 GM and the Seasonic Focus SGX 650W, which uses the same platform as the Ion unit.

Fractal Design made a strong come back with the Ion+ power supplies, and it wants to expand to the SFX market as well, given the release of two SFX Ion models. Fractal's new SFX PSUs come in two flavors, with 500W and 650W capacities, and utilize a Seasonic platform.

Like the Ion+, the Ion SFX Gold units are fully modular and are also equipped with highly flexible cables, which Fractal calls UltraFlex. According to Fractal Design, those cables consist of ultra-high stand count wires and use special insulation that can bend and twist effortlessly, making the installation and cable-rooting processes a breeze.

It is not so common to see a ten-year warranty in an SFX power supply. So far, only Seasonic was brave enough to provide it, but since those Fractal Design PSUs are based on the same platform, they are covered by the same warranty period.


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Manufacturer (OEM)


Max. DC Output



80 PLUS Gold, * ETA-A (88-91%)


* LAMBDA-S+ (35-40 dB[A])


✓ (Fully)

Intel C6/C7 Power State Support

Operating Temperature (Continuous Full Load)

0 - 40°C
Maximum 80% load50°C

Over Voltage Protection

Under Voltage Protection

Over Power Protection

Over Current (+12V) Protection

Over Temperature Protection

Short Circuit Protection

Surge Protection

Inrush Current Protection

Fan Failure Protection

No Load Operation


140mm FDB Fan (S1201512HB)

Semi-Passive Operation

Dimensions (W x H x D)

125 x 65 x 125mm


1.15 kg (2.54 lb)

Form Factor

SFX, EPS 2.92


10 Years

* Not certified yet by Cybenetics. According to our measurements, the PSU falls into those efficiency and noise categories. 

Power Specifications

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Max. Power - Amps20205430.3
Max. Power - Watts100648153.6-
Total Max. Power (W)650650650650650

Cables and Connectors

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Modular CablesCable CountConnector Count (Total)GaugeIn Cable Capacitors
ATX connector 20+4 pin (350mm)1118-22AWGNo
4+4 pin EPS12V (400mm)1118AWGNo
6+2 pin PCIe (400mm+100mm)2418AWGNo
SATA (310mm+200mm+200mm+100mm)2818AWGNo
4-pin Molex (310mm+200mm)1218AWGNo
AC Power Cord (1380mm) -  C13 coupler1118AWG-

Since this is an SFX unit that will be installed into a compact chassis, there is no need for long cables. Long cables can create trouble in small enclosures. Despite the short overall cable length the distance between the peripheral connectors is long, to help users avoid compatibility problems during the cable routing and management processes.

There is only a single EPS connector, which usually is the case for the majority of SFX PSUs. Only the FSP Dagger Pro 650W comes with two EPS, which are on the same cable and use 18AWG gauges, so you cannot fully utilize them. If you need two proper EPS connectors from an SFX power supply, the best option right now is the Corsair SF750.

Component Analysis

We strongly encourage you to have a look at our PSUs 101 article, which provides valuable information about PSUs and their operation, allowing you to better understand the components we're about to discuss.

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General Data-
Manufacturer (OEM)Seasonic
PCB TypeDouble Sided
Primary Side-
Transient Filter4x Y caps, 2x X caps, 2x CM chokes, 1x MOV
Inrush ProtectionNTC Thermistor & Relay
Bridge Rectifier(s)1x
APFC MOSFETS2x Champion GPT18N50D (500V, 18A, 0.27Ohm)
APFC Boost Diode1x STTH8S06(600V, 8A)
Hold-up Cap(s)1x Nichicon (400V, 470uF, 2,000h @ 105°C, GG)
Main Switchers2x Infineon IPP50R190CE (550V, 15.7A @ 100°C, 0.19Ohm)
APFC ControllerChampion CM6500UNX
Resonant ControllersChampion CM6901T6
TopologyPrimary side: Half-Bridge & LLC converter Secondary side: Synchronous Rectification & DC-DC converters
Secondary Side-
+12V MOSFETS4x Nexperia PSMN1R8-40YLC(40V, 100A @ 100°C, 3.25mOhm @ 150°C)
5V & 3.3VDC-DC Converters
Filtering CapacitorsElectrolytics: 9x Nippon Chemi-Con (4-10,000h @ 105°C, KY), 3x Nippon Chemi-Con (105°C, W), 1x Nichicon (4-10,000h @ 105°C, HE) Polymers: 4x United Chemi-Con, 20x FPCAP
Supervisor ICWeltrend (OCP, OVP, UVP, SCP, PG)
Fan ModelGlobe Fan S1201512HB (120mm, 12V, 0.45A, Fluid Dynamic Bearing Fan)
5VSB Circuit-
Rectifier1x MCC SBR (45V, 10A @ 90°C)
Standby PWM ControllerExcelliance MOS Corp EM8569

As we already mentioned, this unit uses the same platform with the Seasonic Focus SGX 650W, which we reviewed a while ago. This is a new Seasonic design featuring a half-bridge topology on the primary side, which is enhanced by an LLC resonant converter for restricted switching losses. On the secondary side, a synchronous rectification scheme is utilized for the +12V rail, while a couple of DC-DC converters generates the minor rails.

The quality of the parts is top-notch. All filtering caps are provided by Japanese manufacturers  Chemi-Con, Nichicon, and FPCAP), and besides electrolytic caps, a large number of polymers is also used. Lastly, the cooling fan measures 120mm; it is provided by Globe Fan and uses a fluid dynamic bearing with a long lifetime.

Although the transient filter is complete, from components, still we measured some high EMI peaks at low frequencies.

The single bridge rectifier is bolted on a heat sink. Afterward, we meet the APFC converter, which uses two Champion FETs and a single boost diode. The bulk cap is by Nichicon and has enough capacity to provide a pretty long hold-up time. 

The main switching FETs are two Infineon IPP50R190CE.

The +12V FETs, four Nexperia PSMN1R8-40YLC, are installed on the solder-side of the PCB. 

Several polymer caps are at the front of the modular PCB, providing an extra ripple filtering layer. 

The soldering quality is good, with all joints having the proper amount of solder, and there are no long component leads. 

It is tough to install a 120mm diameter fan in such a compact chassis, but it helps the most in keeping the noise output low, while at the same time, it offers adequate airflow. Unfortunately, in this PSU, the fan profile is aggressive, so the overall noise output is quite high. 

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Aris Mpitziopoulos
Contributing Editor

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