SilverStone SX1000 1000W SFX-L Power Supply Review


The SilverStone SX1000 is the first SFX-L power supply we have seen here at TheFPSReview. However, SilverStone has been a major player in this segment for a very long time and has produced some of the highest-quality SFX and SFX-L units we have seen over the years. On top of that, this unit is a departure from the platforms used in their most recent SFX units which topped out at 750W.

Today, we are moving up to a massive 1000W in a package just slightly bigger than those 700W/750W SFX units which should make things a bit more interesting. So, does this unit stack up to the high marks of the previous units from SilverStone, or does it come up a bit short? Let’s see.

Build Quality

Today’s SilverStone SX1000 starts things off with a build quality that is very good for what it is (much like SilverStone’s other small power supplies we have seen). The exterior represents a clear link to those small SFX units including the most recent SFX750 when it comes to the unit’s appearance. Instead of just getting the usual huge (relatively speaking) power label we get actual branding on this unit in addition to the good cables and a nice finish.

The integration is remarkably clean for how small and crowded this unit is (just like we saw with SilverStone SFX units). The component selection includes Rubycon standard electrolytics paired with Unicon solid capacitors. There is also a dual ball bearing today which will be of interest to our quiet cooling enthusiasts out there since this is not one of their favorite types, but it is rugged. The documentation with this unit is excellent as always from SilverStone.

Load Testing

Today’s SilverStone SX1000 started off testing in very good shape. We saw voltage regulation of up to 0.14v on the 12v rail, 0.07v on the 5v rail, and 0.07v on the 3.3v rail. These values are a bit behind what we have seen from previous SilverStone SFX units but they occurred over a much larger load range and would still be very good even with a full-sized ATX12/EPS unit!

In addition to that, we saw efficiency that ranged from 88.90% to 91.02% efficient at 120v AC input and 87.18% to 90.18% efficient at 100v AC input. These numbers would be very good for any unit, but this is not just any unit it is a 1000W SFX-L unit! On the flip side, this unit did miss its advertised 80 Plus Platinum levels by up to 1%.

When we look at the Transient Load Tests results for the SilverStone SX1000, we see that the results are very good. When directly loaded, the 12v rail showed a peak change of ~305mV, and the 5v rail had a peak change of ~45mV. During the 12v load, the unloaded 5v rail saw a peak change of ~45mV. In absolute terms, these results are very good. In relative terms, these numbers are a bit better given the size constraints placed on this unit and the capacity crammed into those size constraints.

DC Output Quality

The DC Output Quality results for the SilverStone SX1000 were good. We saw peak ripple/noise values of just ~70mV of ripple/noise on the 12v rail, ~25mV on the 5v rail, and ~25mV on the 3.3v rail. These values are well within specification limits and that means, at a minimum, good in absolute terms. That said, they are hovering around 1/2 of the ATX12v/EPS specification limit so we would like to see them a bit lower. Then again, we do have to consider the capacity and the package we are looking at today. This is a lot going on in a small package so these values are just a little easier to say ok to than they might otherwise be.


Today’s SilverStone SX1000 is not a tiny capacity unit, but it is trapped in a tiny enclosure which means that quiet operation might be a bit of a challenge. On top of that, SFX and SFX-L units are often used in situations where noise is a real concern so people are going to cast a very suspicious eye on this unit. Compounding things even further today is the fact that the hybrid fan mode in the fan controller is paired with a dual ball-bearing fan instead of an FDB fan.

However, while quiet cooling enthusiasts will poo-poo this unit for its fan, I don’t believe it is fair to say the fan alone is at fault for the noise levels today. Yes, at above 50% load this unit is noisy in our testing. However, above 50% load means it is above 500W in a very small and cramped package. When this unit was speced out for 1000W the whole quiet thing was almost certainly a lost cause and, I believe, that may be why the more robust dual ball bearing was selected in place of the less robust but quieter FDB fan.

Basically, SilverStone wanted a reliable long-lived 1000W unit and the dual ball bearing fan gave the best shot at that. Since quiet was already off the table then, this fan makes a lot of sense. And, above 500W output, a lot of noise.

Final Points

The SilverStone SX1000 is a very good unit that is squeezing an obscene amount of power out of a very small package. The SX1000 gave us very good/excellent build quality, very good/excellent voltage regulation, good DC Output Quality, and very good Transient Load results. That said, there were one or two things to quibble about.

First, the efficiency was a bit off the mark and the unit is not what we would call quiet after about 50% load. Then again, you can only get so much out of a unit when you shoehorn this much power into this small of a package. So then, what are mostly very good/excellent ATX12v/EPS results in an SFX-L form factor unit going to cost us?

Today, we find that the SX1000 can be had for around $317.97. Let’s all take a moment to step back after seeing that. That is, probably, the most expensive 1000W power supply that I have seen in the last 5-7 years. That is a lot to swallow. The thing is, though, you would be hard-pressed to find another 1000W power supply that is as good as this in as small of a package.

Now, with a price like $300 that definitely makes this unit a niche product. You are going to need a very specific edge use case in order to justify an outlay like that even in these times of a distorted market. However, if you are in that edge use case there is nothing else that will due, so the price is almost irrelevant as you are going to be a buyer.

For the rest of us, this is one of those products that we look at and go “You did it. You crazy son of a bitch. You did it“. For some of us, that novelty may also be worth the cost of entry, because you sure aren’t going to run into many other people sporting this kind of unit in their system and that is one of those things that is cool to do just because you can.


TheFPSReview Silver Award
SilverStone SX1000 1000W SFX-L Power Supply
Paul Johnson
Paul is a long time PC hobbyist and tech enthusiast having gotten his start when he broke his first C64 quickly followed by breaking his first IBM XT. Most notably however, for 12 years, he served as the Power Supply Editor for one of the truly early, groundbreaking, and INDPENDENT PC enthusiast sites ([H]ardOCP) until its mothballing in April of 2019. Paul now brings the same flair and style of his power supply reviews to

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