SilverStone SFX Series ST45SF 450W Small Form Factor PSU

When building a SFF computer, sometimes the stock PSU comes up short in the power department. SilverStone now has a solution to this problem with the introduction of the SFX series ST45SF PSU. With more and more options for parts to choose from in a SFF build, it is not unheard of to have a full sized graphics card installed. Most of the higher end cards will have additional power requirements that cannot be fulfilled by a mere 300-350W PSU. Of course the PSU’s that have enough power have typically been of the full sized variety that will not fit into the tiny cases of a SFF machine. We built a system using SilverStone’s new SG05 SFF case and put this PSU in place of the stock 300W that came with it. Will the ST45SF be able to handle our fully loaded PC? Let’s find out!  For full specs, visit the product page at SilverStone’s website.

Packaging and Accessories

The tiny box is a good indication of the tiny PSU that lies beneath the slick packaging. The ST45SF is packaged securely with a bubble wrap bag over the PSU. Included in the box is the user manual, power cable, bracket for mounting into a ATX PSU opening, black case screws and some wire ties.

Exterior

The build quality is on par with the SilverStone brand. The PSU is heavy, which usually indicates the quality of the components beneath the cover. The cables are mesh covered and are pretty good in length for a SFF build, but may require extention cables if this were to be used in a standard case. The cables are also attached, no modular ability here. We were happy to see a dedicated on/off switch (a feature that some of their full sized PSU’s lack). There is no switch for selecting the line voltage as this model is auto ranging. The +12V rail is rated for 36A, and should be plenty for any video card that will fit into a SFF enclosure. The ST45SF has active PFC and an 80 plus bronze efficiency rating. The PSU has a great cable selection that should suffice for most small builds.

Cables and Connectors

The ST45SF includes the following power connectors:

• 24 / 20-Pin motherboard connector
• 2 x 4-Pin Peripheral connector
• 3 x SATA connector
• 2 x 4-Pin Peripheral connector and 1 x 4-Pin Floppy connector
• 8/6-Pin PCIE connector and 6-Pin PCIE connector

Interior

The interior is packed for a PSU this small.  A silent 18dBA 80mm fan cools the ST45SF.   The PSU uses a 85°C capacitor, which is fine considering this unit is only a 450W model.

Testing

We installed the ST45SF into our SFF build consisting of :

• SilverStone SG05 SFF case
• SilverStone NT06-E fanless CPU cooler
• SilverStone SOD01 slim optical DVD combo drive
• Intel E8400 Core2 Duo CPU
• Zotac G43-ITX motherboard
• 4GB of Corsair DDR2 800 memory
• BFG GTS 250 video card (requiring 1x 6pin power cable)

The above image is the power supply voltage tolerances chart. All ATX v2.2 PSU’s should have voltages that fall between these minimum and maximum voltages. The ST45SF had the following voltage readings:

*These numbers represent only one PSU and should not speak for the entire line of power supplies. You should always check voltages on a new PSU to make sure they are within accepted ranges.

ST45SF Voltages

+12V = 11.85V

+5V = 5.01V

+3.3V = 3.420V

Conclusion

The ST45SF is another win for SilverStone. The PSU is a high quality product that definitely fills a void in the SFF market by providing options for those that wish to build a tiny PC crammed with a lot of components. After testing the PSU in our SG05 SFF case, we moved it to our HTPC case (GD05) to see how well the ATX PSU bracket worked. The 450W PSU had no trouble running our PC, however we had to rotate the PSU with the fan facing UP in order to be able to plug in the 20+4 power connector into the board. The cables are a bit short. The length of the cables in a SFF case are great. We can safely recommend the ST45SF for it’s ability to fill a necessary spot in a growing SFF market. MSRP for the ST45SF is $69.99 which is an excellent value for that much power in a package this small.