Fractal Design Ion SFX 650G Power Supply Review: SFX Perfection

The Fractal Ion SFX 650G

Introduction and Key Features

Today we are taking our first look at Fractal Design’s new Ion SFX 650G power supply. The Ion SFX Series includes two models: the SFX 650G and SFX 500G. Both power supplies feature a compact SFX-L chassis that accommodates a 120mm cooling fan along with a semi-passive Zero RPM mode for silent operation at low power. The PSU comes with fully modular cables and is certified to meet the 80 Plus Gold efficiency criteria. Fractal Design has partnered with Seasonic to be their OEM and the Ion SFX power supplies are backed by a 10-year warranty.

Fractal has a well-earned reputation for producing outstanding enclosures but they might not be the first name you think of when shopping for a power supply. However, if you are in the market for an SFX power supply, the Ion SFX series should be given serious consideration for your next Small Form Factor build!

Fractal Design Ion SFX 650G PSU Key Features:

• Small Form Factor (SFX-L) design (63.5 x 125 x 125mm)
• 80 Plus Gold certified for high efficiency
• Semi-passive Zero RPM mode allows silent operation at low-mid power
• Tight voltage regulation with low AC ripple and noise
• All-modular, UltraFlex™ DC cables for easy cable routing
• 650W continuous power output at 40°C (520W at 50°C)
• 120mm Fluid Dynamic Bearing (FDB) fan for quiet, reliable operation
• Premium Japanese 105°C capacitors for enhanced reliability
• Powerful single +12V rail with 54A capacity
• Support for high-end GPUs with four PCI-E 8/6-pin connectors
• Includes SFX-to-ATX mounting bracket
• Safety Protections: OVP, UVP, OPP, SCP, OCP and OTP
• MSRP for the Ion SFX 650G is $109.99 USD
• 10-Year warranty

Specifications

The Fractal Ion SFX 650G power supply is rated for a combined, continuous output power of 650 watts at 40°C (or 520W at 50°C). The PSU incorporates a single +12V rail that can deliver up to 54A (648W). The power supply includes universal AC line input (automatically adjusts the AC line voltage) and active PFC, which makes the unit more environmentally friendly to the local power grid.

Fractal Design Ion SFX 650G PSU Specifications:

Packaging and Parts

The Fractal Ion SFX 650G power supply arrived packed inside a shrink-wrapped retail box showcasing the unit’s features and specifications. The power supply is wrapped in a black fabric bag and protected by thick foam inserts.

In addition to the power supply, the box contains a power cord, mounting screws, wire ties, cable ties, a User Manual, SFX-to-ATX adapter bracket, and a bag containing the modular cables.

Seven modular cables handle the power distribution. All of the cables feature UltraFlex™ insulation and high strand count wire for enhanced flexibility and to assist in easy cable routing. The 24-pin ATX cable is sleeved while the other cables are flat ribbon-style. (See table above for cable lengths and connector count).

A Detailed Look

The Fractal Ion SFX 650G power supply enclosure is painted with a two-tone satin black/Gunmetal finish. The back panel includes an On-Off switch, AC receptacle and stylized grill.

The power supply uses a 120mm fan made by Globe Fan for cooling. The fan (S1201512HB) is rated for 0.45A at 12 VDC and features a Fluid Dynamic Bearing (FDB) for quiet operation and long life. The front panel on the Ion SFX 650G incorporates eight modular cable connectors, all nicely labelled and color coded. Note that all of the modular cables are intentionally rather short as this power supply is designed for use in small form factor cases.

Here are a few pictures showing the layout and components inside Ion SFX 650G power supply. Fractal is using Seasonic as their OEM; a very good choice in our opinion. The overall layout, soldering, and build quality appear to be excellent.

The power supply features a modern circuit design to meet the 80 Plus criteria for high efficiency and uses DC-to-DC converters on the secondary to produce the +3.3V and +5V rails from the +12V output. All of electrolytic capacitors are Japanese made 105°C parts with additional solid polymer caps used throughout. For example, the main bulk capacitor is made by Nichicon and rated for 470uF, 400V, and 105°C.

Testing Methodology

Establishing an accurate load is critical to testing and evaluating a PC power supply. PCPerspective’s power supply test bench can place a precise DC load on the PSU under test. Each power supply is tested under controlled, demanding conditions up to its maximum rated load (at 40ºC). Our current suite of tests includes:

• DC Load Regulation
• AC Ripple and Noise
• Efficiency
• Differential Temperature
• Noise

The Fractal Ion SFX 650G power supply was evaluated on both features and performance. A full range of equipment was used to test the power supply under controlled load conditions.

• (2) CSI3710A Programmable DC load (+3.3V and +5V outputs)
• (4) CSI3711A Programmable DC load (+12V1, +12V2, +12V3, and +12V4)
• (2) 200W Precision resistor load bank (+12V5 and +12V6)
• Switchable precision resistor load bank (-12V and +5VSB)
• Agilent 34401A digital multimeter (Accuracy ±0.0035% vDC)
• Extech 380803 Power Analyzer (Accuracy ±0.5% of full scale)
• DS1M12 “StingRay” digital oscilloscope (20M S/s with 12 Bit ADC)
• Extech Model 407738 digital sound level meter (Accuracy ±1.5 dB)

The following cables/connectors were used to connect the power supply to the PC Perspective power supply test equipment.

• (1) 20+4 pin ATX
• (1) 8-pin EPS/ATX12V
• (4) 6-pin PCI-E
• (6) SATA
• (2) Molex

Test Results

DC Output Load Regulation

To simulate demanding and maximum loading conditions, the Ion SFX 650G power supply was connected to the load testers and supplied with a constant 120 VAC. In this test we are interested in seeing how well a PSU can maintain the various output voltages while operating under different loads.

The ATX12V V2.2 tolerance for voltages states how much each output (rail) is allowed to fluctuate and has tighter tolerances now for the +12V outputs. We have included a second table of expanded tolerances (±1% to ±6%) for reference.

The following tables list the DC voltage results for the Fractal Ion SFX 650G PSU while operating on 120 VAC, 60 Hz.

The power supply produced excellent voltage regulation on all of the DC outputs with the three main rails staying within 1% of the recommended ATX guidelines; a very good start!

AC Ripple and Noise on the DC Outputs

The amount of AC ripple and noise present on the DC outputs was checked using a digital oscilloscope. This AC component may be present in the KHz range where most switching power supplies operate or it may be more prevalent at the 60 Hz line frequency. We adjust the O-scope time base to look for AC ripple at both low and high frequencies. The ATX12V V2.2 specification for DC output noise/ripple is defined in the ATX12V Power Supply Design Guide.

Ideally we would like to see no AC ripple (repetitive) or noise (random) on the DC outputs – the cleaner the better! But in reality there will always be some present. I measured the amplitude of the AC signal (in millivolts, peak-to-peak) to see how well the power supply complied with the ATX standard. The following table lists the ripple/noise results during all of the load tests for the main output voltages of interest.

Even at full load the Ion SFX 650G power supply exhibited very good AC ripple and noise suppression with the results staying well below the ATX recommended guidelines.

Efficiency

Efficiency is defined by the power output divided by the power input and is usually expressed as a percentage. If a PSU were a 100% efficient (which none are) 650 watts of AC power going in would result in 650 watts of DC power coming out (with no waste heat to dissipate). In the real world there are always inefficiencies and power is lost in the form of heat during the conversion process. Newer revisions to the ATX12V Power Supply Design Guide V 2.2 have continued to increase the efficiency recommendations for PC switching mode power supplies and now lists both required and recommended minimum efficiencies.

We measured the AC power input to the Fractal Ion SFX 650G power supply with an Extech power analyzer while the total DC load was found by adding all the individual +3.3V, +5V, +12V, -12V and +5VSB loads together.

The overall efficiency of the Ion SFX 650G is very good and easily meets the 80 Plus Gold guidelines, even when operating on 120VAC and at elevated temperatures.

80 Plus Program

Note: Tests conducted at room temperature (25°C)

Differential Temperature and Noise Levels

To simulate a demanding environment, some of the warm exhaust air from the PSU under test is recirculated back to the intake through a passive air duct, which allows the PSU air inlet temperature to increase with load, up to 40°C.

The differential temperature across the power supply was calculated by subtracting the internal case air temperature (T in) from the temperature of the warm exhaust air flowing out the back of the power supply (T out).

Thermocouples were placed at the air inlet and exhaust outlet. The ambient room air temperature was 23ºC (74ºF) +/- 0.5ºC during testing.

• T out = temperature of air exhausting from power supply
• T in = temperature of air entering power supply
• Delta T = T out – T in

Sound pressure level readings were taken 3’ away from the rear of the case in an otherwise quiet room. The ambient noise level was ~28 dBA.

*Fan not spinning

The Fractal Ion SFX 650G power supply started out silent and stayed that way through the 50% load test. The fan started spinning as soon as we entered the 75% load test but stayed relatively quiet. At full load with an elevated ambient temperature, the cooling fan noise became noticeable.

Final Thoughts and Conclusions

Fractal’s new Ion SFX 650G power supply delivers a near-perfect combination of features and performance wrapped-up in a compact chassis. We appreciate the extra space the lengthened (SFX-L) case makes for component layout, airflow and a 120mm cooling fan. The power supply easily delivered 650 watts of combined DC output and exhibited excellent voltage regulation with low AC ripple and very good efficiency.

The Ion SFX 650G features all modular UltraFlex™ cables, which by the way are intentionally short, for easy installation. At low to mid-power in Zero RPM mode the PSU is silent. At higher power, once the fan started to spin, it remained relatively quiet thanks to a high-quality fan with a Fluid Dynamic Bearing.

Note: the Ion SFX series power supplies come with an SFX-to-ATX adapter bracket so you can install the Ion SFX 650G into a standard ATX power supply opening.

The current PC power supply market is mature and already crowded so it’s nice to see a new player entering the arena with a well thought out product; just the right combination of features, performance, aesthetics, warranty support and pricing. Well done!

• MSRP for Fractal Ion SFX 500G is $89.99 USD
• MSRP for Fractal Ion SFX 650G is $109.99 USD

Strengths:

• Small Form Factor (SFX-L) design (63.5 x 125 x 125mm)
• 80 Plus Gold certified for high efficiency
• Semi-passive Zero RPM mode allows silent operation at low-mid loads
• Tight voltage regulation with low AC ripple and noise
• All-modular, UltraFlex™ DC cables for easy cable routing
• 650W continuous power output at 40°C (520W at 50°C)
• 120mm Fluid Dynamic Bearing (FDB) fan for quiet, reliable operation
• Premium Japanese 105°C capacitors for enhanced reliability
• Single +12V rail with 54A/648W capacity
• Support for high-end GPUs with four PCI-E 8/6-pin connectors
• Includes SFX-to-ATX mounting bracket
• Safety Protections: OVP, UVP, OPP, SCP, OCP and OTP
• OEM partner is Seasonic
• 10-Year warranty
• Competitive pricing

Weaknesses:

• None noted

If you are in the market for an SFX power supply for your next SFF build, one of the new Fractal Ion SFX series power supplies should be on your short list; highly recommended.

Our thanks to Fractal for sending us the Ion SFX 650G PSU to review.