SilverStone ST1000-PTS Power Supply Review: Downsizing To The Extreme

Specifications and Part Analysis

The major assets of the SilverStone ST1000-PTS power supply are its compact dimensions (142mm or 5.59 inches depth), low noise output and the highly efficient platform, which meets the 80 PLUS Platinum and Cybenetics ETA-A+ efficiency standards. Is this is enough though to justify the high asking price of $254 (£195)? The fact is that there are better performing products in the same price range, so SilverStone has to either lower this unit's price or release a new version with improved performance, to keep up with the tough competition from Corsair, FSP and Seasonic.  

We have already evaluated the ST1200-PTS, so it was a matter of time before we put its smaller brother on the test bench. The SilverStone ST1000-PTS has the same compact dimensions with the 1200W unit, but because of the smaller capacity it achieves a lower power density score which still looks impressive though, at 554W per liter (it is 664W per liter for the ST1200-PTS). Clearly SilverStone participates in an endless race with one goal in mind, to downsize its power supplies as much as possible. Some years ago, a PSU with only 140mm length had a hard time achieving 750W max power and we see nowadays similar dimension units going up to 1200W, while still keeping the noise output low.

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Inside the box, you’ll find several useful accessories. In addition to usual stuff like, fixing bolts and zip ties, it also includes several Velcro straps and a magnetic dust filter, which can be attached at the PSU's fan grille and prevent dust build up at its internals. 

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The ST1000-PTS looks like a 600-750W unit rather than a 1kW one, thanks to its small dimensions. Normally 1kW units have a length of 160-180mm, but the ST1000-PTS is 140mm long.

Specifications

Power Specifications

Cables and Connectors

All cables are modular and there are two EPS connectors along with eight PCIe ones. Actually the ST1000-PTS uses exactly the same cable configuration as the ST1200-PTS, meaning that it offers a great amount of connectors. The distance between the peripheral connectors is ideal at 140-150mm, but for the PCIe ones, a 100-110mm clearance would be better, since the corresponding sockets on power hungry graphics cards are usually installed side by side.

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Component Analysis

We strongly encourage you to have a look at our PSUs 101 article, which provides valuable information about PSUs and their operation, allowing you to better understand the components we're about to discuss.

The ST1000-PTS uses the same parts with the ST1200-PTS, with the only difference being the addition of a small number of CapXon polymer caps on the secondary side. We expected to see differences in the PFC and the main switching FETs and in the FETs that regulate the +12V rail, but there are all the same. Even the bulk caps are identical, which is weird!

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The platform is provided by Enhance Electronics and, on the primary side, a full bridge topology is used along with an LLC resonant converter. On the secondary side, a synchronous rectification scheme is used for the +12V rail, with eight FETs handling this rail, and the minor rails are generated through a pair of DC-DC converters. The electrolytic filtering caps are provided by respectable manufacturers and are of high quality. The majority of polymer caps is provided by Unicon; we also found several CapXon polymer caps.

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