Introduction

Silverstone is a familiar name in our PSU testing facilities, and today we will be looking at the fifth power supply from Silverstone. It is also the second fanless power supply we've reviewed, following the Amacrox Calmer 560. Silverstone has left a consistently good impression with high quality and very good results, and the 700W Decathlon was especially impressive with its near-silent performance. Obviously, we're going to get true silence today since the Nightjar doesn't have a fan. The cooling is done with high efficiency large heatsink sitting on top of the power supply. The market for these power supplies is somewhat limited, since airflow is vital to modern PC systems. Using a power supply that doesn't contribute at all to system cooling - and in fact can do the exact opposite - typically causes issues with temperatures.

To avoid more serious cooling problems, fanless power supplies are generally limited to lower power ratings, such as the 450W model we're reviewing today. This also makes sense considering any system with need for more power will have high-end graphics cards and processors that run noisy fans. The usefulness of a fanless power supply is thus very limited, or at best it's a way to reduce (but not fully eliminate) noise. The market where they make the most sense is for HTPCs. They need to run as quietly as possible since they are in the same room where you want to watch your favorite movies. They also don't need a ton of power (usually) since most of the components are relatively low power - all you need is a moderate CPU and a GPU with H.264 decoding support (which you can now get with certain IGPs). We already tested a fanless power supplies with a peak output of 560W, but 400W will be just fine for all but the most demanding HTPCs. (Ed: So Anand's monster with 20TB of storage or whatever doesn't qualify?)

The label indicates a peak output of 450W, which as mentioned should be the maximum this sort of power supply needs to offer. We also find an intelligent setup within the lower voltage rails. The 3.3V and 5V rails are rated at only 22A for the 3.3V rail and 15A for the 5V rail. Together they can still supply 130W, which is sufficient for modern systems. The single 12V rail is rated at 35A, which makes us wonder if anyone cares about ATX safety regulations.

Packaging and Appearance

The Nightjar comes in a very sleek package and lies inside thick plastic foam. A change for Silverstone with this power supply and its package is that they're silver and not the usual black. We also find the standard manual, power cord, straps, and screws delivered with the package.

As stated, the power supply is silver, and it's perforated on all sides for better venting. The top is composed of a thick aluminum block with fins on the top. In between the fins are small openings to get air inside of the housing for additional cooling. Some electronic parts such as the coil from the primary stage have heat-conducting tape attached to transfer the produced heat to the housing, which then acts as a giant cooler for the inner parts. The power supply casing has an unusual amount of screws, which seems to be necessary to establish contact from all sides to provide the maximum cooling possible without a fan. The front has two LEDs; the first indicates the power supply is switched on since you don't hear it, and the second one shows the user if the temperature inside of the PSU is within operating limits.

Cables and Connectors

All of the cable harnesses are sleeved up to the first connectors, but the sleeving starts just after the cables come out of the housing, which seems a bit cheap. That said, we have to admit there's not much space inside due to the large heatsinks, so we will forgive Silverstone this gaffe. It's nice to see that there are actually two PEG connectors attached to the power supply, allowing users to install even high-end graphics cards with two jacks. Considering this is a silent power supply and high-end CPUs are anything but, how many will actually do so is a different question.

With a minimum length of 50cm (20 inches), all of the ATX connectors and cable harnesses are sufficiently long for the intended market. Six Molex and six SATA connectors help to make this power supply stand out from other fanless power supplies.

Internals

For any tech enthusiast with a little knowledge, the inside of this power supply brings a feast of quality and is extremely clean. We haven't seen such good build quality in a long time, and there is simply nothing negative to talk about. Soldering is very clean and there are only small drops of glue to hold the coil and other components in position.

As for the capacitors, we see Nippon Chemi-Con in the primary (three 150µF with 450V) and secondary as well as Teapo and some solid state caps. The PCB has heat conductive tape on the bottom so that it can dissipate some of the heat to the housing of the power supply. From the design, it isn't quite clear who actually builds this unit, but the UL number shows the PCB comes from Jiangsu Difeida Electronics. Jiangsu is the province around Shanghai where many electronic companies are expanding since places like Shenzhen and Dongguan are becoming less desirable. FSP also has a factory in this region. Another UL number on the package of the unit suggests Etasis is the manufacturer, but we found other typical markings that clearly show this unit is built in an Enhance factory.

Testing with the Chroma ATE Programmable Load

Our test equipment consists of two Chroma programmable DC Loads that enable us to test power supplies with an output of up to 1500W. The biggest advantage of the Chroma DC Loads is simply the high precision it provides. It can measure differences as small as 0.001V and 0.0001A, which will provide us with best-in-class results.

When programming the Chroma with specific amounts of load calculated according to the ATX norm, we are able to load power supplies to an exact percentage. We can now show results at every specific percentage needed. To get the best overview of a power supply, we load each unit with 10%, 20%, 50%, 80%, 100%, and 110% of the specified output. This is easy to calculate for a 1000W power supply: the 10% load is 100W and 110% load is 1100W. Remember that this is the amount of power the PSU delivers; due to inefficiencies, a power supply will actually draw more power from the wall.

Note: If you would like to know more about our testing methodology, equipment, and environment, please read our PSU testing overview.

We have added an additional 10% on the highest load to see how the units perform with overload. This test will be performed in all future reviews. The overload test is performed at room temperature as well as under more stressful conditions; to ensure we are not too cruel to the power supplies, we will keep the ambient temperature at 50°C in the stress test. Experience shows that many units can stand the overload at room temperature but will experience problems with higher temperature and overload together. Only the best-built units will survive this.

The Testing Environment

There is one flaw in testing power supplies with programmable loads while trying to measure the sound pressure levels at the same time. Because the programmable loads get very loud, there is no chance of hearing the power supply on the test stand. In order to make accurate measurements of the noise levels we needed a way to separate the test unit and the programmable loads. Our solution was to build a very thick box around the unit.

We concluded that a five-layer box with a total thickness of 6" (15cm) containing two layers of wood and three layers of special foam would suffice. It is designed as a box within a box. The inner box does not touch any part of the outer box, making it difficult for acoustic noise to pass through in the form of vibration. Each box is isolated on both sides with a layer of heavy foam that is normally used to insulate engines. On the inside we have an additional layer of 4" (10cm) thick pyramidal foam on every side of the box to eliminate the acoustic waves coming from the test object as well as we can.

To ensure a completely closed system we installed the printed circuit board that the connectors of the power supply are attached to inside the anechoic room/box. In other box designs, you would need to put all the cables through the wall. Unfortunately, that would result in the inside of the box not being fully isolated anymore. Our design keeps everything that needs to be connected inside of the box and maintains isolation.

DC Output, Ripple, and Noise

The new Silverstone Nightjar really shows its potential in voltage regulation. Though we see 1.5% to 2.5% regulation with the lower voltage rails, the 12V rail is regulated to within a 1% margin, which is simply amazing for such a unit. Even at up to 50°C the voltage doesn't drop under 12.00V, making this a very stable unit.

3.3V rail max

5V rail max

Channel 3 represents the 3.3V rail, Channel 4 the 5V rail and Channel 1 12V. Ripple is quite high for the 3.3V rail as we measured 39.8mV, with 50mV allowed according to PSU ATX standards. The 5V rail show signs of even higher ripple as we see large spikes and the ripple is a little out of specs. At 31mV, the 12V rail does better and is well within specs.

Efficiency, PFC and Temperatures

Using 230VAC, the Nightjar delivers efficiency of 88% from 225W to 375W. It then drops to 86%, which is still an excellent result. As the graph shows, the efficiency isn't as good with lower input voltages; optimal efficiency is obtained with loads of at least 100W, and the range of maximum efficiency is not the same as long as with 230VAC. Of course, even with loads of 50W to 75W it still manages at least 80% efficiency; while 88% might be more desirable, we are only talking about a difference of ~5W. What's the point in reaching 88% efficiency at 250W if you only need 50W?

The power factor correction looks good with lower input voltages, but we have seen much better results for 230VAC.

This unit does not have an exhaust temperature, which is why we attached the diode we normally use to measure the exhaust temperature to the power supply casing to measure the outside temperature. After loading the power supply for a while, we eventually reach a temperature that would allow us to cook an egg on the surface, but in fairness we have also seen hotter temperatures with some fan-cooled power supplies.

The outside surface reaches up to 58°C with 30°C ambient temperature. That's definitely not a bad result, and seeing the two heatsinks top out at 70°C makes us confident of its power supply's ability to run in systems with a single fan. However, temperatures are still increasing as we put an additional load on the PSU, and a higher ambient temperature would definitely result in higher PSU temperatures. We would be extremely hesitant to run such a power supply in a system where the ambient case temperature can reach 50°C or higher -- at least not without additional case fans, which defeats the purpose of the fanless power supply. Silverstone agrees with this, as they state the power supplies designed to operate in a 30°C ambient temperature.

Conclusion

The Silverstone ST45NF Nightjar definitely raises the bar for fanless power supplies, as it delivers one of the best performances from a fanless unit we have seen to date. It even manages to surpass some of the lower quality fan-cooled power supplies. The build quality also sets new standards, as it is excellent. Only a few power supplies have had such high-grade workmanship. The choice of components is generally good, with the important 12V rail using Nippon Chemi-Con and solid state caps and the lower voltage rails getting by with Teapo. The three main capacitors also come from Nippon Chemi-Con and have to fit under the large heatsinks, which is why there are three instead of only one large capacitor. Given the lack of space, Silverstone's internal layout makes sense.

Thinking back on previous fanless power supplies, there's usually a very limited number of cables and connectors. The Nightjar offers a wide range of connectors, which we would expect from a normal 450W unit. There are six SATA and Molex connectors and two PEG connectors, one of which is a hybrid 6/8-pin connector. The length of the cables is good as well, as we measured a minimum of 50cm.

Moving on to voltage regulation, Silverstone achieved very good results, particularly with the 1% regulation from the 12V rail. Even with a higher ambient temperature of 50°C applied for about 20 minutes the 12V rail remained stable and never dropped under 12.00V. Silverstone states clearly that this PSU is rated at 30°C ambient temperature, which is why we primarily confined our testing to such an environment. The internal heatsinks don't exceed 70°C, and while that's very hot it's still remarkable for a fanless unit. After all, last year we tested several fan-cooled models that had similar heatsink temperatures.

It goes without saying that throughout testing we never heard any noises from this power supply -- and that includes noise caused by electronic components. If you're looking to put together an HTPC that makes as much noise as your stereo amplifier (i.e., none), the Silverstone Nightjar would be a good place to start.

Finally, let's talk about efficiency since this tends to be one of the major selling points of modern power supplies. Even here the Silverstone Nightjar can set new heights and tops most other competitors. 88% efficiency is very high, and it even manages to stay at that level from 225W to 375W. There's no need to panic even at higher loads, since it stays above 86%. All this of course is with an input voltage of 230V; things aren't quite as good with 120VAC or 90VAC, but the efficiency is still high even if the PSU doesn't manage to stay at maximum efficiency over as larger range.

Considering all of the above factors, we certainly don't expect the price to be all that great; the performance and quality delivered will cost more to manufacture. $170 to $190 isn't the most expensive power supply we tested, but it is quite a lot of money for a 450W unit. On the other hand, if you want to run a truly silent HTPC without having to skimp on performance in order to keep power requirements in check, the Nightjar appears to be an ideal PSU. Prices in Europe start at 140€ to 150€, including the 19% tax. Whether or not these prices are acceptable isn't for us to decide, but rather for the people who are interested in this sort of power supply. Not only is the Nightjar completely silent, but it manages to outperform many fan-cooled power supplies with stable rails and high efficiency. At least for the price you won't be purchasing a lemon.