Enermax DigiFanless 550W


This will be the first fanless PSU unit I have reviewed. Digital PSUs are becoming more popular due to the control you have over the PSU with software and no noise. Enermax lately has been changing some things around for the better. They have been redesigning most of their products with better features, Such as longer modular cables, better cable quality, and better case design. They have also made huge strides in their fan department. I know this because I have tested previous products and have seen the changes over time. Let’s see if this PSU with its unique marketing as a digital  fanless PSU can make this product stand out among its major competitors.

The specifications & features are as follows:

Brand Name Enermax
Item model number EDF550AWN
Item Weight 8.1 pounds
Product Dimensions 13.5 x 4.5 x 10 inches
Item Dimensions L x W x H 13.5 x 4.5 x 10 inches
Color Black
Power Source corded-electric



IMG_1586  IMG_1587

We can see from the front of the box that we possibly have a special product on our hands. The word “DIGIFANLESS” to me sounds like a digital fanless PSU. The back of the box goes over all the potential best features of this product. We see ZDPMS which stands for “Zero Delay Power Monitoring System“. Typically these type of digital PSUs have fans with software to monitor them, this is the first I have seen that is fanless.

IMG_1604  IMG_1607

The accessories include:

  • DigiFanless 550W PSU
  • Enermax bag for all your modular cables
  • Enermax Cable ties
  • Digifanless manual
  • AC cord
  • AC cord holder
  • Enermax case badge
  • Nicely individually sleeved modular cable sets

IMG_1613  IMG_1615

These have been the best modular cables Enermax have made so far. They are all individually sleeved black, and it’s great they went away from their standard multi yellow colored cables included in most of their PSU packages. I only hope they continue to use these nice black cables in future packages. Great job improving your individual modular cables Enermax.


IMG_1596 IMG_1600

Unboxing the unit we see a label that says attention. Basically, the important thing here is do not cover this top vent, and this is due to the fanless design. You need that top vent for proper heat dissipation. You will also have air vents on each side of the PSU as well. The Digifanless 550W is the worlds 1ST digitally controlled fan less PSU, and is rated as 90 PLUS ready, with 80 PLUS Platinum certification.

IMG_1597  IMG_1649

The front has a full modular system. You have your ZDPMS port which is a connector that is a USB 2.0 header for your motherboard to the PSU. This allows the ZDPMS software to talk to the PSU. This “DIGIFANLESS” offers two 12V rails which out of the box is configured as a multi rail system. For this low Wattage of a  PSU this is overrated. Each rail combined is rated for 45A. You might as well of kept this PSU a single rail system. I will discuss later how we can change that. The front modular connectors have your 24 pin main which has the 8pin EPS attached to the same modular cable, Two GPU modular connectors, and your three SATA or Molex connectors. Quick note here, notice how when mounted as intended that your motherboard main power and CPU connector is all the way to the left. This might pose a length problem in certain cases. Personally, I had no trouble reaching things on my test bench.

IMG_1603  temp.JPG

The back as well offers proper ventilation with a smaller Enermax logo, an On/Off switch, and an AC power plug connector. Notice how I mentioned above how the PSU needs to be mounted with the top vent up; well these screw holes here are meant to mount the PSU traditionally down, like PSU models with fans. If you have a case that does offer two sets of PSU mounting holes, which most modern ones do, then you will be fine. If your case doesn’t offer this, then this PSU will not work with your current setup as intended. Do some research on your case before purchasing this model. For this PSU the 40°C temperature limit for a fanless unit is great at full power. This creates a 0dBA operation with no noise.

IMG_1629  IMG_1633

With the lid removed, we see the massive heatsinks used for the 40°C ambient limit. The surface uses an extended heatsink design to control the temperature. The unit also offers its copper bridge array which ensures tight regulation to your components with little energy loss. The PCB in the DIGIFANLESS is 2x2oz which offers low power loss,and higher efficiency. The PCB also has DC to DC load compatibility for C6/C7 sleep states.

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This PSU offers PFC control. PFC is Power Factor Correction which helps regulate the PSU and keep it within spec. Line filtering is done where the AC power cord is plugged into using one X cap and two Y caps. Model LL25XB60 are the bridge rectifiers used. The two Toshiba diodes are also for PFC behind the heatsink. The control board next to it is for controlling PFC and is labeled CM6502 for single PFC, and is designed to meet the 90 + spec. This is good for total efficiency.


The board above has a PIC 32 chip and is used to control the PSU over the Enermax software. It connects directly to the front modular board. This board also offers the chip for OCP protection. In fact, this PSU offers Enermax SafeGaurd technology. This has OCP, OVP, UVP, OPP, OTP, SCP, and SIP voltage protections. If you don’t know what any of these are you should look them up, as it would take to long to explain each on in detail, but basically they keep your PSU from melting or causing serious damage.

IMG_1638  caps

All aluminum electrolytic caps are Nippon Chemi-con. These are awesome 100% 105°C Japanese capacitors. The PWM controller on this board uses a CM6901 for voltage control.

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Testing / Software

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Before I even started with hooking it up to my test bench, I wanted to use my new PSU tester to see if the voltage was in spec, and the PSU was still good after disassembling it. The voltages across the PSU managed to all stay within about 3% of the specification for each rail. There is sometimes minimal drop in voltage as with power regulations.

My test bench is as follows:

  • Motherboard- EVGA Z170 Classified K
  • CPU: Intel Core I7 6700K
  • Network Card- Netgear AC 1200 USB
  • Cooler- H80i V2
  • Memory- Anarchy X 16GB DDR4 2800MHz
  • Video Card: Nvidia GTX 1060
  • Storage- PNY CS2210 480GB / Samsung 950 pro m.2 512GB
  • Power Supply- Enermax DIGIFANLESS 550W
  • OS: Windows 10 x64 Pro
  • Headphones- Creative H7

The CPU was overclocked to 4.5 GHz for benchmark purposes, and the memory was set to its XMP profile.


I’m going to test the loads for standard gaming and then by overclocking my test system. I will test the Watts used, and will be using a KILL A WATT to test Wattage. Please keep in mind that each system is different and actual loads can vary greatly even with similar hardware. I will be gaming using DOOM, and using the system on 100% full load with Adia64 extreme. I will also be monitoring and changing settings with the Enermax ZDPMS software.


The ZDPMS software is truly unique and allows a bit of software control over your PSU. You can download this software and get more information here. This software as you can see allows the user to control and read real-time power consumption, efficiency, and internal temperature. Here you can control the OCP trip points, look at your AC input values, and control voltage regulation to a small degree.

switch  Rail

This software also gives you the ability to switch between multi-rail and single rail 12V configurations. Personally, I prefer the 12V single rail as it just allows the Amps on the OCP to be set higher. Instead of the 35A trip point, the single rail sets a higher 50A limit. Now you can also configure the OCP warning points manually, but only to the extend of 4 Amps each, and it doesn’t matter if you’re on a single or multi rail to change these. You can’t go above the limit set, but you can lower it 4 Amps.


Notice in the first software picture that I was only using 53 WATTS at system idle, but putting a load on the PSU using Adia64 at 100% load, I am pulling 123 WATTS. This is also with a CPU overclock of 4.5GHz. I will show the actual load from the KILL A WATT for idle stock and overclocked voltages in the chart below. This should show if the software is accurate or not, and show what to expect at a minimum and maximum values based on my clock speeds.

watts.png  2818321131183400025

The load on the PSU is measured to get a general idea across various systems in respect to Watts consumed. Your worst case depending on your overclock, mine @4.5 GHz isn’t bad at 132W. The software is pretty close to what the KILL A WATT was calculating. I’m not even coming close to even using the 550W. The idle 55W is also fantastic for power consumption  at system standby. You will also notice above in the screenshots of the software that the PSU efficiency is also where it needs to be for “Platinum Certified”, as well as the temperature staying in spec. Over all this PSU handles its voltage regulation and efficiency really well. There is no noise level testing because this PSU is silent with its fanless design.


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This PSU does have a few cons. For starters make sure that your case offers the right screw holes for the intended configuration. The other issue is with the Modular rails for the main connectors are all the way to the left. This may not pose a problem, but in some cases, it will. Check for clearance and make sure you have enough room to reach your motherboard connectors.


There is still a lot to love about the Enermax DIGIFANLESS PSU. For starters, it’s the world’s 1ST fanless all digital PSU. The software functions well and has awesome voltage regulation. My favorite part of this PSU is the ZDPMS software and the real-time control it gives you. The modular cables are also the best I have seen in an Enermax product yer. I hope they continue this trend and believe they will increase sales with even this simple of a change. This DIGIFANLESS PSU is dead silent with 0dBA with its fanless design. This is ideal for home theater, or anyone looking for a low noise solution. I definitely recommend the Enermax DIGIFANLESS 550W PSU, and you can buy it right now Amazon for $215.00








Enermax DigiFanless 550W

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