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Review: SilverStone ST50NF Nightjar 500W Silent PSU

by Tarinder Sandhu on 4 September 2012, 09:56 3.0

Tags: SilverstoneTek

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Testing results

Our Chroma load-testing procedures can be found at this link.


Load 10pc 25pc 50pc 75pc 100pc
Efficiency 74.9pc 86.5pc 88.8pc 87.6pc 87.1pc

Starting off a little slow but then ramping up very nicely, real-world efficiency is simply outstanding for a fanless PSU. Indeed, the 25-100 per cent numbers are consistent against top-quality, fan-assisted supplies. Good work here, SilverStone.


In terms of regulation, we're looking at just how well the supply is able to hold to the various lines. The ATX spec. has a +/- 5 per cent leeway on all but the -12V line.

Line/Load 3.3V 5V 12V
10 per cent -1.1pc +0.6pc +0.2pc
50 per cent -0.6pc -0.2pc -0.8pc
100 per cent -0.8pc -0.5pc -1.0pc

The regulation, too, is excellent for any kind of PSU. Lines stay very close to the ideal at all times, irrespective of load. And remember, there's not a peep out of the supply when providing rock-solid regulation.

Regulation - cross-load

How about providing uneven loads that stress particular voltage rails? In the first attempt, we've put 35A on the 12V rails, and 1A on the 3.3V and 5V rails. This can actually be somewhat typical for a system heavy on graphics and CPU power. In the second, we've turned the tables and gone for 10A on both the 3.3V and 5V rails - highly unlikely in a real-world environment - and just 2A on the 12V - even more unlikely!

Line/Load 3.3V 5V 12V
Cross-load 12V focus -0.9pc 0.2pc -0.6pc
Cross-load 3.3V/5V focus -0.8pc 0.4pc -0.5pc

Hammering one part of the PSU power delivery while using just a small portion of the other can throw cheaper supplies of out kilter. The numbers barely seem to move as the supply's delivery is pushed and pulled apart. We had to run this test multiple times to confirm the result.


Line/Load (mv - p-p max) 3.3V 5V 12V
10 per cent 12mV 10mV 20mV
50 per cent 28mV 20mV 50mV
100 per cent 40mV 30mV 90mV

The ATX v2.2 spec states that the maximum permissible ripple is 120mV for the 12V line and 50mV for others.

PSUs convert AC power into DC, but doing so requires the AC waveform to be suppressed. What we're really testing here is the quality of the supply's rectifier and any smoothing capacitors in getting rid of this unwanted up-and-down ripple.

The first chink in the Nightjar's armour is presented in the ripple tests. 5V ripple performance is good, granted, but the 3.3V and 12V's is close to the outer fringes of the (basic) ATX v2.2 specification.


Temperatures Ambient Heatsink
10 per cent 25.2°C 26.5°C
50 per cent 28.1°C 36.9°C
100 per cent 29.8°C 52.1°C

We have to use different testing methodology here because the design prohibits us from placing temperature probes in the correct spots within the chassis. We've used an infra-red temperature gun and shown the temperature of the upper heatsink in the above table. As such it cannot be compared to anything that we have reported on before. Further, out-of-a-chassis testing means that no airflow is directed at the PSU. Ambient temperature is represented by a thermocouple placed 1cm away from the side of the PSU.

Accompanied by the red light and becoming toasty under 100 per cent load, the supply continued to provide 500W of power from a 230V AC source.


This one's easy; it's silent.