Today's Hard|Forum Post
Today's Hard|Forum Post

Enermax Digifanless 550W Power Supply Review

Enermax joins the ranks of the fanless computer power supply builders. These are of course a must-have for those enthusiasts looking for a zero noise profile computer build. Many times these sorts of builds of course suffer from very hot environments, so fanless PSUs are a perfect fit for our testing criteria.



The Enermax Digifanless 550W is the latest in a long line of power supplies that we have seen from Enermax and it is the first fanless unit we have seen from Enermax. Actually, this is one of the few fanless units we have seen overall. However, all of the previous fanless units we have seen have been good performers. So, with Enermax' generally good track record and the high quality nature of the previous fanless units we have seen we have high hopes for this unit today. High hopes though aren't results so we still have to wonder; did this unit go quietly into the night? Or did this unit soar quietly to new heights? Let’s see.

HardOCP’s testing methodology is intended to very much push power supplies to their advertised wattage rating in temperatures that will represent some of the hottest computer enthusiast cases. So if a unit passes all our testing it is definitely not something to take lightly. In fact we expect more power supplies to fail our testing than make it through unscathed.

Build Quality

The build quality of the Enermax Digifanless 550W starts things off today on a very good foot. Externally, the Digifanless 550W does start off a bit mixed as the fit and finish has a tough, well appointed aesthetic that fits with the Enermax branding but the cables are all individually sleeved making each bulkier than necessary and prone to knotting, twisting, splaying, and generally making a mess. However, Enermax has at least mitigated this somewhat by zip-tying these in various places along the length and it has paired these with with a fully modular design. When we move to the interior of the unit, things are again very nice though there are a few points of note. To start things off, the topology is very modern with an interesting arrangement of the 12v power components and the DC-DC VRMs on the secondary. Everything in this unit is heavily heatsinked, due to it being fanless, which makes the remainder of the build look busy. In reality it is very clean with the heatsinks that occupy so much space being necessary for this type of unit. The soldering extremely clean and well done. The component selection features very nice Nippon Chemi-con standard capacitors through out while the solid capacitors take a definite step down to Enesol and then once more to DuraTech. The integration on the single layer PCB is also generally good. This is all backed up by massive amounts of documentation about both the unit and the software control aspects but, importantly, the software is not included which is a serious downside when it comes to inclusiveness and initial functionality of the product. Lastly, the Digifanless 550W is backed up by a 5 year warranty from Enermax which is very good.

Load Testing

Today, the load testing results for the Enermax Digifanless 550W were simply outstanding and provide what will likely be the best aspect of testing for this unit, or for most units. The voltage regulation saw the 12v rail experience a drop of just 0.03v during testing and the minor rails had a peak change of 0.04v during testing. Relative to the competition, these values do not trail any comparable unit if we include the "overclocking" results of the Kingwin Stryker 500W as it was also cleanly better than the SilverStone ST50NF and in line with Nightjar 520W. When we look at this unit’s efficiency, we see that it was 88.93% to 92.38% efficient at 120v and 88.10% to 91.07% efficient at 100v during our tests today. Then, when we ran the 80 Plus tests, we saw efficiency values of 90.55%-92.48%-90.11% for the Digifanless 550W which put this unit right in its claimed 80 Plus Platinum category. So, the Digifanless 550W is starting off as one of the best fanless unit we have seen to date.

The Transient Load Tests results for the Enermax Digifanless 550W are passing and good given the category we are looking at today. When directly loaded, the 12v rail showed a peak change of ~400mV and the 5v rail had a peak change of ~140mV. The unloaded 5v peak change during the 12v load was ~90mV. These results put this unit behind the SilverStone Nightjar 520W but ahead of the Kingwin Styker 500W and the SilverStone ST50NF. So, while slipping a little compared to what we in the regular load tests, this unit is still coming in near the head of the pack in this aspect of our testing which results in another very solid result.

DC Output Quality

Moving on to the DC Output Quality today, we see that the Digifanless 550W is passing but the Digifanless 550W is moving back in the pack slightly once more. During our testing, the peak 12v trace amplitude was ~30mV while the peak 5v and 3.3v trace amplitudes were ~25mV. Each of these results are well within the ATX12v specification limits but in the case of the minor rails we are hitting ~1/2 of the ATX12v specification limit so these are not the best results we have seen from comparable products. Indeed, when we look at that competition, we see that this unit trails the Kingwin Stryker 500W and the SilverStone Nightjar 520W. On the upside, and it is somewhat of a small upside mind you, this unit does end mixed compared to the much older SilverStone ST50NF. So, this would make this part of testing the worst part of the Digifanless 550W's testing today and tied for last is not exactly a great result even when it is a passing result.


As with previous fanless power supplies, the Enermax Digifanless 550W is silent. As such, users looking for quiet operation can look at this unit as a viable option.

Paul's Thoughts:

It has been a solid two years or more since the last time we saw an Enermax unit that was truly an award worthy product. On top of that, none of the previous Enermax branded units that we have seen that were produced by someone other than Enermax have been even close to contenders. Today though, today, it seems as if Enermax might have finally gotten its grasp on how to be a solid product designer when it does not also own the production capacity to pair with its designs which is great to see. As it stands, the Digifanless 550W is a product that actually reminds me of the Enermax of the past where you could count on a product being something great just by the name on the box. And, make no mistake, the Digifanless 550W is a great product.

However there has been a catch greatness over time and that catch has always been that the Enermax name carried a price premium. Those price premiums used to be easy to swallow because you knew at least you didn't have to worry about product quality but more recently they have been somewhat hard to swallow on some products. Now, if Enermax keeps that issue in check today then Enermax could have a winner as this unit is a real contender no matter the price. Heck, this unit is even a leader in some aspects as it does feature a 5 year warranty (which is longer than the SilverStone Nightjar 520W), this unit does have excellent documentation for its software features, and this unit did perform like what we would expect from a class leader. All of those things together, say buy, buy, buy, buy, buy and, if nothing else, it is good to see today that Enermax has a product that hits all of the right metrics before we get to the pricing because it has been a while and these kinds of products have been missed.

The Bottom Line

The Enermax Digifanless 550W PSU is excellent. That was a very short sentence that covers most of the pertinent information for this unit today. Seriously, if we look back at the results today we find that this unit had excellent build quality, it is literally silent, it had truly outstanding voltage regulation, etc. If we were to quibble with anything we saw today we would complain about the DC output quality that was still in specification but trails some of the other fanless units we have seen, save for one. Overall, when we look at this unit relative to the competition we see that this unit is better over all than the SilverStone ST50NF and Kingwin Stryker and on par with the truly excellent SilverStone Nightjar 520W; but with a bit more capacity and a bit better efficiency which might actually give this unit the nod there too. So, where does that leave us then? Pricing.

When it comes to pricing, we see that this unit is carrying an MSRP of $225 (This PSU is not yet for sale in North America, so no street price to compare.) and that right there took a product that was truly excellent by performance metrics and killed any value it had. Sure this unit runs like a champ, but the SilverStone Nightjar 520W is just about a dead match for this unit in performance while being $75 less than this unit today. The Enermax Digifanless 550W is the most expensive fanless unit we have ever seen by a good margin. So, at the end of the day, we have a truly excellent product being offered at an extremely expensive price. That is something users are going to have to weigh when they look at this Digifanless 550W sitting next to the competition. How much is the name and the software you very likely won't use more than once worth? $75? That will be up to you to decide.

In terms of review performance, the Enermax Digifanless 550W PSU is a Gold Award unit, however the tremendously premium pricing does detract from its overall value in our eyes.

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Enermax Digifanless 550W PSU

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