ocaholic - PSUs > Enermax DigiFanless 550W Review

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Preview

Page 2 - Preview

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Delivery and Specifications

With the Enermax DigiFanless 550 Watt you get a fully modular digital power supply, which comes with sleeved a set of sleeved cables right from the factory.

Cables
Cable	Length
1 x ATX 20+4 pin	65 cm
1 x EPS/ATX 12V 4+4P(8) pin	65 cm
2 x PCI-E 2 x 6+2 pin	65 cm
2 x 4x SATA	45, 60, 75, 90 cm
1 x 4x Molex + 1 x Floppy	45, 60, 75, 90, 105 cm
1 x ZDPMS	65 cm

The Enermax DigiFanless 550W PSU comes with two PCIe 6+2 pin cables, which in total feature four connectors. Therfore it's possible to power up to two graphics cards with power. Overall connectivity is good for a 550W PSU. There are also two SATA cables with eight connectors included in the bundle. Especially modders will love the fact, that the cables have been sleeved already by Enermax.

Specifications
Voltage	Current	Power
+ 3.3 V	20 A	100 Watt	550 Watt (Total)
+ 5.0 V	20 A	100 Watt
+ 12 V1	30 A	540 Watt
+ 12 V2	30 A	540 Watt
- 12 V	0.5 A	6 Watt
+ 5 Vsb	2.5 A	12.5 Watt

The EDF550AWIN has been 80Plus Platinum certified. This means, that the efficiency of this PSU should be above 90% at 20% load, above 92% at 50% load and above 89% at 100% load.

At this point the feature list:

80Plus Platinum
OVP, UVP, OCP, SCP, OPP, OTP
Dimensions (W x H x D): 150 mm x 86 mm x 175 mm
Warranty: 5 Years
Price: is estimated to be around 200 Euro

Page 3 - Delivery / Specs

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A Look Inside

The first hint that this is a high Quality PSU you perceive when looking at its casing. What we find is a nice design and thick steel plates. Working our way inwards we also see exceptional soldering quality and also the layout looks very clear.

Right at the input there is one X capacitors and two Y capacitors. On the main PCB the transient filtering stage continues with one Y2 capacitor and four polyfilm caps and there are two ferrite coils, one CM choke and one MOV (Metal-Oxid-Varistor). Overall the transient filtering stage is very well done.

On the primary side of the PCB we find a TOP265EG integrated Off-Line switcher made by Power Integrations which helps increasing energy efficiency in general. Next there is the main transformer but unfortunately there is no brand name visible. We guess Enermax is using a Viking B-2 in this case. Going a little further we find four massive K20J60U mosfets from Toshiba, which have been attached to large passive heatsinks.

Still on the primary side we also see a big APFC capacitor from Nippon Chemi-Con (KMQ series; 470uF and 400V at 105°C). Capacitance is well chosen for a 550W PSU and we always prefer to see one big APFC cap instead of two small ones. Furthermore Enermax is making use of a very capable Schottky diode (C3D08060A, 600V, 11A) for rectification. Apart from that, still on the primary side, there is another Y capacitor and a small Viking B-2 class 130B transformer.

On the secondary side 3.3 and 5V are generated from 12V using DC-DC conversion. The converters are located on a daughter PCB. Unfortunately we could not disassemble this part of the power supply, which is why we don't know what chips are being used here. Voltage modulation is handled be two additional PCB, one on each side of the PSU and they've been interconnected. DC filtering is done using Nippon Chemi-Con capacitors, which resembles the high quality of this unit.

Page 4 - A Look Inside

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Software

As we mentioned before the Enermax DigiFanless 550 Watt is a digital Power supply, which allows manufacturers to create completely new tools to manage the unit. In this case Enermax created their own management software, which they call ZDPMS and stands for "Zero Delay Power Monitoring System". Using this tool you can monitor total output power, efficiency and temperature. Apart from that you can change voltages in real time. You can even go to the point where you change from single rail to multi rail and vice versa. Should there be a need you can also overvolt the 12 Volt rail to 12.40V.

To see what the DigiFanless 550W digital power supply can do in real-world, we used it to power different systems with different graphics cards. In this case load was applied using Prime95 for CPU and FurMark for the GPU. Once we've installed an AMD Radeon R9 290X monitoring the PSU becomes really interesting. We noticed that the system needed 362 watts and it was running at 93% efficiency and 36°C. Regarding amperage on the 12V rail 35A were used.

After stressing on AMD Radeon R9 290X we decided to install two GeForce GTX 980 in SLI and we were surpriced that this PSU was still capable of powering the test system, especially if we consider the efficiency. According to ZDPMS the system was burning 557 watt total output power at 92% efficiency and the temperature inside the PSU was still no higher than 36°C. In this case the PSU was running in single rail mode. Switching to multi rail and still powering an GTX 980 SLI rig we recieve +12V2 OCP warning and the efficiency remains at 92%.

Page 5 - Software

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Result Analysis and Discussion

Efficiency 115V
Load	Pin(W)	Pout(W)	Efficiency
20 %	121.73	111.00	91.19 %
50 %	289.96	268.01	92.43 %
100 %	550.73	550.73	91.83 %

The 80Plus Platinum certification requirements (90% - 92% - 89%) are surpassed especially at 20% Load. The full Load efficiency is a bit higher at 230V AC. This is the case with most of todays PSU's an it mainly originates from the reason of lower losses in the AC filtering stage and the PFC at 230V AC. The 230V AC 100% Load efficiency is 91.83%.

Output Stability - Crossload
Load	Rail	Loading(A)	Output(V)	Total Power (W)
20 %	5V	2.01	5.10	10.0
	3.3V	2.01	3.39	6.6
	12V	7.51	12.08	90.0

50 %	5V	5.01	5.08	25.0
	3.3V	5.01	3.37	16.5
	12V	18.19	12.07	226.0

99 %	5V	10.01	5.05	50
	3.3V	10.01	3.34	33
	12V	37.46	12.01	449

Noise
Load
20 %	passiv
50 %	passiv
100 %	passiv

Voltage regulation of this PSU is very good. It makes use of a DC-DC approach, which means, that the 12 Volt rail is being used to generate 5 and 3.3V. This is a very modern approach, and since the Load is mainly on 12V it makes a lot of sense. Like most PSU, which use this topology, the voltage regulation and crossload testing does not present a problem.

Noise/Ripple
Voltage	Noise/Ripple Vpp
5V	0.008
12V	0.011
3.3V	0.007

The noise/ripple values you can see here come from a Chroma test report, which was provided by the manufacturer. The noise values are simply excellent. The quality of the DC output signal is just excellent, and in comparison with many other PSUs outstanding.

Page 6 - Result Analysis and Discussion

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Conclusion

With the DigiFanless 550W, Enermax offers a digital PSU, which is available for 200 Euro these days. Connectivity options are good and there is a total of four PCIe 6+2 connectors included in the bundle. For a 550W PSU the efficiency surpasses 80Plus Platinum standards with huge margin especially at 20% load.
This unit is very well manufactured and the DC output quality is simply excellent. Another neat feature, especially for silent systems is the fact, that this is a completely passive cooled power supply. Therefore you won't be hearing any noise from this unit. Another great sign of quality is, that the efficiency does not drop much between 50 and 100% Load. Additionally, because of it's very low ripple/noise, this PSU is very well suitable for high-end PC audio, where low ripple and noise values are what you're looking for.

Overall the Enermax DigiFanless 550W is one excellent power supply. Thank you very much for the good work Enermax!

We rate the Enermax DigiFanless 550W with 4.5 out of 5 possible stars. Although build quality and features are excellent the price is really steep.