A highly affordable SFX unit that offers decent performance and a silent operation under normal conditions, thanks to the 92mm fan that equips it. If you don't have a problem with its native cables and your system's consumption usually is in the 200-300W range, then the ST45SF will fully cover you needs. Besides the affordable price its strong advantages also include the in spec hold-up time and a full protection features set.
Full power at 46°C
Load regulation (+12V)
Ripple suppression (for the standards of the SFX category)
Full protection features set
Accurate power ok signal
Silent at normal conditions
Duro Bearing fan
OPP should be set lower
Low number of SATA connectors
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Features & Specifications
SilverStone has a large portfolio of SFX-based products, from high-end and expensive ones to mainstream models that cost significantly less. One of the company's most popular SFX PSUs is its ST45SF, which offers enough capacity to power a mid-range PC. It might lack modular cables and it isn't particularly efficient, but an affordable price tag helps compensate. In short, the ST45SF is within reach of anyone needing a compact power supply.
A quick look at the product's webpage tells us that there are two versions of this unit: v2.0 and v3.0. The older implementation is made by FSP, features a 80mm fan, and is rated at up to 50ºC for continuous full-load output. The ST45SF v3.0 is based on a Sirtec platform and uses a 92mm fan, so we expect it to be less noisy. Unfortunately, the updated model is only specified for continuous full-load output at up to 40ºC.
The mainstream ST45SF has a low efficiency rating in both 80 PLUS and Cybenetics programs. Moreover, all of its cables are hard-wired, which has the potential to make installation in a space-constrained chassis difficult. But native cables are the safest/easiest way to keep costs down without compromising performance. We'd rather see fixed cables and good components inside than modular cables and low-quality caps or FETs.
SilverStone's reliance on a 92mm cooling fan, the largest diameter that an SFX PSU can accommodate, is a smart move. The larger the fan, the slower it needs to spin for any given airflow compared to smaller fans. Because of its low efficiency, the ST45SF doesn't have a semi-passive mode. But we don't see the lack of a semi-passive mode as a disadvantage. In fact, we prefer a fan to constantly remove heat; this helps prolong the PSU's lifetime. And in such a compact chassis, achieving semi-passive operation is a real challenge. The tiny PCB is cramped with components, reducing the amount of air that can flow through and raising the temperature inside compared to normal ATX models.
Because this is an entry-level model, the ST45SF's specifications aren't particularly impressive. It's 80 PLUS Bronze- and ETA-S-rated. For noise, it carries the LAMBDA-S++ badge from Cybenetics, meaning that overall output lands between 30-35 dB(A). As mentioned, the third-gen version's temperature rating is 40°C, while the second-gen model gets a 50°C rating. All essential protection features are present, including the ever-important over-temperature protection. And SilverStone's three-year warranty is ample, given the ST45SF's price tag.
|Total Max. Power (W)||450|
The +12V rail can deliver the PSU's full power on its own. This is a clear indication that voltage regulation modules handle the minor rails. The maximum combined output at 5V and 3.3V is quite high for a 450W SFX-based power supply, while the 5VSB rail is also capable enough.
Cables And Connectors
|Description||Cable Count||Connector Count (Total)||Gauge|
|ATX connector 20+4 pin (305mm)||1||1||18-20AWG|
|4+4 pin EPS12V (405mm)||1||1||18-20AWG|
|6+2 pin PCIe (410mm+150mm)||1||2||18-20AWG|
|Four-pin Molex (300mm+200mm) / FDD Adapter (+200mm)||1||2 / 1||20-22AWG|
Although you get an ample number of EPS and PCIe connectors for this category, we'd like to see one or two more SATA connectors thrown in. All of the cables are pretty short, since the ST45F is expected to live in a small chassis. Fortunately, though, the distance between connectors is quite long. That should help avoid installation problems.
Since this PSU features a single +12V rail, we do not have anything to say about its power distribution.
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Aris Mpitziopoulos is a Contributing Editor at Tom's Hardware US, covering PSUs.
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