Cold Test Results (Room Ambient Temperature)

For the testing of PSUs, we are using high precision electronic loads with a maximum power draw of 2700 Watts, a Rigol DS5042M 40 MHz oscilloscope, an Extech 380803 power analyzer, two high precision UNI-T UT-325 digital thermometers, an Extech HD600 SPL meter, a self-designed hotbox and various other bits and parts. For a thorough explanation of our testing methodology and more details on our equipment, please refer to our How We Test PSUs - 2014 Pipeline post.

Due to the unique thermal design of the Nightjar NJ450-SXL, we had to change our testing methodology quite a bit. As there is no airflow to assess, we placed a sensor on the bottom side of the chassis and measure its surface temperature instead. Note that these thermal results are not directly comparable with those obtained by testing regular air-cooled products.

The SilverStone Nightjar NJ450-SXL easily honors its 80Plus Platinum efficiency certification, significantly surpassing the minimum requirements of 92%/94%/90% efficiency at 20%/50%/100% load respectively (230V AC input). It has an average efficiency of 92.9% across its nominal load range, a relatively high figure even for an 80Plus Platinum certified unit. The efficiency drop when the unit is powered from a 115V AC source is small, reducing its average efficiency across the nominal load range down to 92.5%. Note that the efficiency drop is more severe at higher loads but negligible, or even negative, when the unit is very lightly loaded.

As expected from a well-designed passively cooled device, the surface temperature of its heatsink increases almost linearly and in near-perfect alignment with the unit’s thermal losses. It does reach over 40°C when the power supply is heavily loaded but that is a perfectly safe figure for an advanced PSU. The internal temperatures of the PSU over its primary and secondary side MOSFETs are acceptable, with the primary side getting a little bit hotter than the secondary side.

The SilverStone Nightjar NJ450-SXL SFX PSU Hot Test Results (~45°C Ambient Temperature)
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  • ingwe - Thursday, April 4, 2019 - link

    This looks like a great PSU overall, but a passive PSU would make me pretty nervous about longevity.
  • Exodite - Thursday, April 4, 2019 - link

    I can only offer anecdotal support but I don't think you should worry about that, as long as the PSU itself is of good quality.

    I've been using the same Seasonic SS-FL460 (a fanless 460W, Gold-rated unit) since 2011 and while it's still powering the same i7 2600K I bought along with it it's scaled perfectly all the way up to a Vega 56, 4 HDDs and a SSD.

    I don't game 24/7 by any means but even when stressing the unit as far as my setup allows (Prime95 + FurMark) it doesn't get particularly warm.

    Unfortunately my particular unit isn't the perfect example of the benefits of fanless PSUs as it has some audible electrical noise under particular loads, so there's that. :)
  • jeremyshaw - Thursday, April 4, 2019 - link

    Audible electrical noise is the exact reason I sold off my last Seasonic passive PSU. Mine made more noticeable noise than the fan did on another Seasonic PSU. Unacceptable, IMO, so I actually haven't bought another Seasonic since then (apparently a good choice, since they have since languished in PSU design, even if their quality remains reasonably high).
  • Exodite - Thursday, April 4, 2019 - link

    Completely understandable.

    I'm in the market for a new desktop later this year and if I end up replacing the chassi and PSU as well it probably won't be with a fanless model. Not because of any issue with passive cooling but rather the noise.

    I'm still interested in Seasonic primarily I admit but since I value silence and the electrical noise of the new models are an unknown to me I'm inclined to go with a traditional solution.
  • FreckledTrout - Thursday, April 4, 2019 - link

    I have a Seasonic Prime Ultra 850 Titanium SSR-850TR in my desktop build with a Ryzen 1800 and a GTX 1070. Having 850 watts its complete and utter overkill but it's basically fanless unit in hybrid mode for 99% of my usage and being Titanium I don't lose much efficiency running it at 25-40% of max wattage. It also has zero electrical noise that can make out even when I put me ear up to it with the fan not running I hear nothing.
  • Exodite - Thursday, April 4, 2019 - link

    Thank you, that's good information!

    If I do switch PSUs it's likely going to be a Titanium unit, for the 10% efficiency minimum. Hitting ideal efficiency under load is usually easy enough at any load from 25-100% but I'm hoping to improve my efficiency at idle and basic desktop use too.

    A 650W Titanium unit should still be 90% efficient at 65W and that's not an unrealistic figure at the desktop, I think?

    At least that's about what I'm seeing now, though obviously a more modern platform may well draw less power.
  • daniel78R - Thursday, April 4, 2019 - link

    I have a Corsair SF600, in a FractalDesign Node 202 powering a Ryzen 1600X (with Scythe Big Suriken - modified) and GF 1060 and unless I start a game, the PSU does not start the fans, and even when it starts, it is way less noisy than CPU or GPU fans, and they are not very loud either
  • nagi603 - Monday, April 8, 2019 - link

    > At least that's about what I'm seeing now, though obviously a more modern platform may well draw less power.

    Not necessarily, especially for GPUs. (1080 vs 2080 is quite a jump, 180 to 215W) The bump in core count has not resulted in lower idle draws either.
  • emn13 - Wednesday, April 10, 2019 - link

    Although the electrical noise is major irritant for those that suffer from it, it's by no means universal, and it's not just one or two manufacturer's that have this problem. I'm pretty sure it's also not even really model-specific in the sense that even within the same model some batches are problematic, and other's aren't.

    Which means you might want to simply resign yourself to trying several ones, and sending bad ones back, rather than relying on trying to divine some pattern from the online reviews, many of which don't mention this at all.
  • tonyou - Sunday, April 7, 2019 - link

    PSU electrical noises are usually high frequency noises and travel by air, so with NJ450-SXL's external aluminum heatsink shell having no vents, it actually helps reduce those noises better than any PC power supply ever could.

    If silence is your priority, you should give NJ450-SXL a try.

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