Copyright 2010 - K.S. Studios - All rights reserved
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!

Specs

SilverStone SFX Series ST45SF 450W Small Form Factor PSU

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.

4/18/10 -Keith Soreghen-

Packaging

Conclusion

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.

Accessories

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.
Model No. SST-ST45SF
Max DC Output 450W
Load Range
+3.3V
 +5V +12V1 +5VSB -12V
Max (Amps)
21A
 22A 36A 2.5A 0.5A
Peak (Amps)
/
/
/
3A
/
Min. (Amps)
0.1A
0.2A
0.6A
0A
0A
Range (%)
±5%
 ±5% ±5% ±5% ±10%
Line Reg. (%)
±1%
±1%
±1%
±1%
±1%
Ripple (mVp-p)
70mA
 70mA 140mV 70mV 140mV
combined +3.3, +5V 120W
combined +12V 432W / 36A
Input Voltage 90V ~ 265V
Input Frequency Range 47Hz ~ 63Hz
PFC Active PFC（PF>0.95 at full load）
Efficiency 82%~85%（20% to 100% loading）
MTBF 100,000 hours at 25°C, full load
Operating temperature 10°C ~ 50°C
Protection Over current protection
Over power protection
Over voltage protection
Under voltage protection
Short circuit protection
Connectors
1 x 24 / 20-Pin motherboard connector（300mm）
1 x 8 / 4-Pin EPS / ATX 12V connector（400mm）
1 x 8/6-Pin PCIE connector（400mm）
1 x 6-Pin PCIE connector（550mm / 150mm）
3 x SATA connector（300mm / 220mm / 100mm）
2 x 4-Pin Peripheral connector （300mm / 200mm）
1 x 4-Pin Floppy connector（300mm / 200mm / 200mm）
Color Black（Lead-Free Paint）
Cooling System Single 80mm silent fan
Noise Level 18dBA minimum
Dimension 125 mm (W) × 63.5 mm(H) × 100 mm(D)
Weight 1 Kg
Other Includes SFX to ATX bracket for use in ATX case

First Impressions

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.
The ST45SF uses a 85°C capacitor
A silent 18dBA 80mm fan cools the ST45SF
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
A view of the inside of the PSU

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 +5V +3.3V
11.85V 5.01V 3.420V