SilverStone SX700-LPT 700W SFX-L Power Supply Review

SilverStone has a new take on small form factor power supplies it is calling "SFX-L." This new form factor extends the standard SFX size by 30mm allowing SilverStone to install a quieter 120mm fan than the usual higher speed and noisier 80mm and 92mm fans. How does all this work out?


SilverStoneTek is a company best known for its high quality cases but its product lines extend into other components such as cooling, power, fans, storage, and so on. As a company, SilverStone has built up this impressive product repertoire in a very short time having been founded in 2003. Today, however, we are interested in SilverStone's power supplies which are comprised of the Strider, SFX, Nightjar, Gemini, and Zeus model lines that range from 300 watts to 1500 watts DC output. For this review, we are looking at SilverStone’s largest capacity SFX-L series power supply, the SX700-LPT, which is produced in conjunction with Sirfa.

Sirfa Electronics Co., Ltd. is a name that is not that familiar to most users but Sirfa has been around since 1996 when Sirtec established Sirfa as a factory in the Sirtec group on mainland China. In June 2008, Sirtec sold off its interest in Sirfa making the company independent of the Sirtec brand but still in business with High Power. As such, while we have not seen any Sirfa produced power supplies under the Sirfa brand, some of the Sirtec units of the past were produced at the Sirfa facility. Additionally, we have seen Sirfa providing OEM services for Thermaltake, Enermax, PC Power & Cooling, Tuniq, Lepa, SilverStone, and others with very mixed results.

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Does Making the Package a Bit Bigger Make the Contents Better?

Over the years, we have reviewed a large number of standard ATX/EPS power supplies. We have, however, reviewed just a few other form factor power supplies like Auxiliary power supplies, TFX power supplies, redundant power supplies, and SFX power supplies. Today, SilverStone is back with another one of these slightly less common, in the enthusiast realm, form factors with their SX700-LPT. However, where we have seen a few SFX form factor units from SilverStone in the past, today's unit is slightly different in that it is a SFX-L form factor unit. As the SFX-L is a slightly larger form factor than the SFX form factor, there is, obviously, a bit more room to play with. In the past, SilverStone has done well with these smaller units and, certainly, we expect the same again today. However, with a bit more room we expect a bit more out of this unit than we do from its smaller siblings. So, before moving on, let's see what SilverStone has to say about this specialty item:

For small form factor enthusiasts, the standard SFX power supply form factor has excellent combination of size, power, and affordability. At 100mm deep, however, the standard SFX PSU is also limited in fan size to 80mm or 92mm. While advances in engineering and components have made modern high-end SFX PSUs quieter than ever, there is still inherent limitation with these fans’ ability to dissipate heat at maximum loading conditions while maintaining satisfactory noise profile for users sensitive to higher-pitch sounds. With this in mind, SilverStone has released a "lengthened" variation of the SFX form factor called, SFX-L. With 30mm of added depth, a SFX-L power supply has enough room to fit a 120mm fan, thus its maximum load noise can be not only lower in intensity (via slower fan speed), but also lower in pitch (due to larger fan size).

The SX700-LPT marks another milestone in SilverStone’s pursuit of higher quality and more capable small form factor power supplies. At 700W, it includes all features available from top of the line SilverStone PSUs such as 80 PLUS Platinum efficiency, modular flexible flat cables, all Japanese capacitors and advanced semi-fanless capability.

Let’s move on and see what we can expect when a user purchases the SX700-LPT power supply at retail in terms of documentation, accessories, cable count, rail layout, output characteristics, and general build quality.