Power Supply Quality

As part of our testing, we also check output parameters are within specifications, as well as voltage ripple and line noise.

Main Output
Load (Watts) 202.65 W 505.85 W 753.59 W 1001.78 W
Load (Percent) 20.27% 50.58% 75.36% 100.18%
  Amperes Volts Amperes Volts Amperes Volts Amperes Volts
3.3 V 2.27 3.39 5.66 3.39 8.5 3.33 11.33 3.31
5 V 2.27 5.13 5.66 5.08 8.5 5.06 11.33 5.01
12 V 15.1 12.14 37.75 12.13 56.62 12.05 75.5 12.02


Line Regulation
(20% to 100% load)
Voltage Ripple (mV)
20% Load 50% Load 75% Load 100% Load CL1
3.3V + 5V
3.3V 2.1% 12 20 22 26 18 22
5V 2.25% 18 26 30 34 20 26
12V 0.92% 16 32 46 78 76 30

The electrical performance of the SilverStone SX1000 is good and within our expectations for an Enhance platform. Line filtering could use some improvement, as the voltage ripple figures are relatively high, with our instruments recording a maximum of 78 mV, 34 mV, and 26 mV on the 12V, 5V, and 3.3V lines respectively. These figures are adequate, but top tier units easily halve these values. Meanwhile line regulation is significantly better, with the 12V line maintaining a regulation factor of 0.9%. The regulation of the 3.3V and 5V lines is a little higher than 2%, which is enough for a modern design.


Unlike ATX PSUs, SFX designs have still seen significant development over the past few years. Not only has their power output increased considerably, but their overall performance dramatically improved as well. SilverStone is a company strongly focused on the R&D of small form factor cases (SFF), systems, and other related parts. They have several compact cases and products designed for high-end living room systems, including designs that were designed with gamers in mind. Therefore, their efforts to market the very best SFX PSUs available are not unfounded. The SilverStone SX1000 is a noteworthy milestone as it has a tremendously high-power density, delivering power that it would be difficult for a physically larger standard ATX unit to deliver about a decade ago.

While the SX1000 is, for the moment at least, the most powerful SFX/SFX-L unit on the planet, its overall performance left us with mixed feelings. In some ways it feels as if it is a small step back from the SX800-LTI, a unit that delivered better energy conversion efficiency and power output quality. The electrical performance of the SX1000 is not bad at all – it does meet all 80Plus Platinum certification and quality standards with ease – it is just a little worse than its less powerful predecessors. It also struggles to maintain reasonable noise and temperature levels when the load is very high, even when the operating environment is relatively cool. However, due to the possibility of high internal temperatures, the designer is using very high-quality components so that they will not be thermally stressed. This bodes well for the quality and longevity of the SX1000, as these components will perform very reliably under normal operating conditions.

Much like most top-tier SFX units, the SX1000 is struggling to find its identity in the retail market. Its SFX-L design limits its compatibility with SFX cases and there is no adapter to install it inside an ATX-compliant case either – in which case, the length of the cables could be a problem. It is powerful enough and has enough connectors to power a top-tier motherboard and two graphics cards, yet such motherboards and two cards will not fit in the vast majority of SFX-L compliant cases. Only an SFX case designed to hold a top-tier Micro ATX motherboard and four slots' worth of graphics cards would be a reasonable match for the SX1000.

The creation of a powerful gaming small form factor PC for the living room is the heartfelt desire of every serious gamer. Still, few are determined (and deep-pocketed) enough to be able to justify an aesthetically elegant and compact gaming PC with a flagship graphics card in it. Nevertheless, SilverStone’s latest PSU is designed to specifically target that small, yet existent, segment of the market. More pragmatically, perhaps, it could also be used to power systems with a single high-end graphics card while operating near its half capacity, offering top efficiency and reliability. However, the very high retail price of $366 at this writing severely limits the market potential of the SX1000, as only users who do not care about having a budget when building a PC would purchase it. 

Hot Test Results (~45°C Ambient)
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  • romrunning - Wednesday, July 28, 2021 - link

    You can't just generalize that all small form factor PSUs are not worth it. A good PSU is a good PSU, no matter what size. I have a Corsair 750W SFX PSU, and it's perfectly fine and quiet, despite the SFX size. I do not feel I have compromised in any way compared to a full-size ATX 750W, and indeed, I have benefited from the small size in my ITX case. I think all PSUs, large and small, should be judged by their own strengths & weaknesses.
  • Oxford Guy - Wednesday, July 28, 2021 - link

    There is a thing called diminishing returns. The laws of physics can’t be broken via wishful thinking.

    Taking one aspect of design far out causes necessary curtailment(s). If those are something a person can live with (such as a deaf person with a loud PSU) that’s fine but the more niche a design is the less appeal/relevance it will have for the majority.

    Three-wheel microcars have their niche but it’s not a very big one, no matter how ‘good’ they are. Don’t try to drive them at high speeds and don’t expect much if there is a collision with a larger vehicle. They’re fine when they ‘stay in their lane’. No one is going to put a V-8 turbodiesel into one.
  • CheapSushi - Thursday, July 29, 2021 - link

    This is NOT diminishing returns. This is so stupid as a comment. There's even smaller form factors. With Gallium Nitrate they get even more efficient. They get quieter because of higher efficiency. More can be titanium and platinum rated. Seasonic even makes a dual twin 700W PSU in an ATX form factor. Stop holding back the norm. People like you would never let the Industry do ANYTHING different.
  • Oxford Guy - Thursday, July 29, 2021 - link

    Putting the word 'not' in caps isn't a substantive rebuttal, nor is the rest of your post.

    Higher efficiency is available in larger form factors. And... the maximum size of the fan decreases as form factors shrink – something this article pointed out. Smaller fans make more noise for the same level of cooling, typically, if two fans are designed equally efficiently. That is why ATX cases no longer commonly ship with 80mm fans.

    'Stop holding back the norm. People like you would never let the Industry do ANYTHING different.'

    Good ole ad hom... the lubricant of astroturf.
  • Samus - Thursday, July 29, 2021 - link

    What compromise? Not everyone needs a big case to flex their e-peen :)
  • CheapSushi - Thursday, July 29, 2021 - link

    What's that got to do with anything? Case size shouldn't be the deciding factor for making SFX and SFX L the norm, the standard. Silverstone and many others are proving you can make high efficiency high watt in a smaller package with zero real loss to anything in quality and performance.
  • Oxford Guy - Thursday, July 29, 2021 - link

    Oh my. Well... you managed to respond to a bad comment with one that was even less competent.
  • Oxford Guy - Wednesday, July 28, 2021 - link

    ‘This is a strange choice by SilverStone, as the company usually prefers to use sleeve bearing fans because of their lower noise output, even for their top-tier products.’

    Sleeve bearing fans have to be mounted vertically for good longevity, according to everything I’ve read. PSUs are always mounted horizontally.

    Sleeve bearings are also, as far as I know, efficient with no/very low restriction scenarios (e.g. ‘case’ ‘airflow’ fans) but create very little static pressure. So, using a sleeve fan inside a PSU hardly seems optimal in that way either. Should designers begin to mount them vertically...

    FDB and similar ‘modern’ bearings seem to be optimal from both a cooling-per-decibel point of view (with decent, although not always great, static pressure ability) and also can be mounted horizontally.

    Ball bearing fans typically are used for the highest static pressure scenarios, such as mounted to dense radiators. How much less restriction does a PSU like this one have?
  • meacupla - Thursday, July 29, 2021 - link

    The bearing type has little to no factor in determining static pressure or air flow of the fan.

    Sleeve bearing fans just don't last as long as ball bearings, especially in higher temperatures.
    There is a NMB comparison sheet even tells you that sleeve bearings will fail to operate above 70c.

    "Sleeve bearing is quieter" is an outdated convention. Well made ball bearings can run as quiet as sleeve bearings, but cost goes up with tighter tolerances.

    The reason for most static pressure fans using ball bearings or fluid dynamic bearings, is probably because they already require tighter manufacturing tolerances, and using higher quality bearings doesn't increase the BoM by much.
    Where as air flow fans can be made cheaply by skimping on quality and using a sleeve bearing to compensate for the increased noise of poor weight balance.
  • Oxford Guy - Thursday, July 29, 2021 - link

    'The bearing type has little to no factor in determining static pressure or air flow of the fan.'

    I have never seen a sleeve fan that has strong static pressure but I have seen plenty of dual-bearing ball fans that do. They have little space between the blades and, typically, large motor hubs.

    I have read a lot of fan reviews and the review results don't match your claims, nor the claims of Samus. I have also purchased a good number of fans and have looked at what's on offer at retail and online. These magical sleeve-bearing static pressure fans are like unicorns.

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