Measurements: SilverStone SST-ST50NF
Efficiency, According to the 80 PLUS Specification
Efficiency Across the Power Spectrum
The 80 PLUS Bronze efficiency requirements aren't as stringent. So, while the SST-ST50NF does meet the organization's Bronze-level requirements, its efficiency value at low loads is far worse than the values recorded from the other two contenders. At 25 W, its efficiency is only 60%. With that said, it behaves like a typical Bronze-certified power supply, and does not stand out negatively among other Bronze-level supplies.
Unfortunately, the same cannot be said about the ripple voltage on its +12 V rail. At 129 mV, it does not even comply with ATX standards.
On the positive side, the SST-ST50NF sports an above-average hold-up time of more than 40 ms. The Nightjar power supply passes all other tests with flying colors. We measured a temperature increase of 49 degrees Fahrenheit, which is slightly less than the temperature increase of the Seasonic supply. Also, we're fans of the warning LED on the back of the power supply that warns of critical internal temperatures (though we're not sure you'd see it light up behind your PC).
A Peek at the PCB
The first thing we noticed after opening SilverStone's SST-ST50NF was its massive heat sinks covering large parts of the circuit board. This is a stark contrast to the Seasonic X-460.
Obviously, the dramatically larger heat sinks are necessary in light of the Nightjar's lower efficiency rating. At an identical load, it'll dissipate more heat than the 80 PLUS Gold-certified Seasonic unit. We can also see that the SilverStone supply has a well-designed input filter, unlike some low-cost solutions. SilverStone also uses premium-grade components, like Chemi-Con capacitors from Japan and Infineon MOSFETs. Instead of a single high-capacitance capacitor on the primary circuit, four smaller ones are used in parallel, which increases the surface area and thus aids in cooling. Copper shims between the power transistors and the large heat sink also serve to improve cooling.
The manufacturing quality of this fanless supply is impeccable, and the quality of the electronic parts is top-notch as well. However, the out-of-tolerance ripple voltage does raise questions about the electrical quality of this power supply. When we factor in the lower price and higher efficiency of competing models, like Seasonic's X-460, we find it difficult to recommend the fanless solution from SilverStone.
