Seasonic Focus SGX 500W SFX-L Power Supply Review: Top Performance In A Small Package

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Bottom Line

Seasonic's new small form factor units manage to offer good performance without breaking the bank. This is what the majority of users want, a balance between performance and cost, since only a small portion of them is willing to pay a large amount for getting the highest possible performance. Seasonic could easily do 80 PLUS Titanium or Cybenetics ETA-A+, but it chose to use a less exotic design in order to keep the production cost under control, and achieve low price tags, making those products highly appealing to more people. It would be nice though, if the company made a Prime small form factor power supply, which could go head to head with the Corsair SF750.

The Seasonic SSR-500SGX achieves high overall performance, thanks to its super-tight load regulation and the good ripple suppression. The transient response is also quite good at +12V, 5V and 5VSB, while there is room for improvement at 3.3V. In addition, the hold-up time is very long at 23.5ms and the power ok signal is accurate. 

Under normal operating temperatures (28-32 degrees Celsius), the passive operation lasts up to 150-200W loads and it takes more than 390W of load, to enter the noisy 40-45 dB(A) region. The fan speed profile could be much more relaxed, but Seasonic's engineers wanted to remain on the safe side given that this product is covered by a hefty ten-year warranty. I would prefer a shorter warranty (e.g. five years) and quieter operation, though.

The 500W Seasonic SFX-L offering has many good points but not everything about it is perfect. I would like to see more SATA connectors since three are way too few, even for a small form factor unit. Since there are modular sockets available, Seasonic should include an additional SATA cable in the box, as it does with the SSR-650SGX. Another thing that I noticed is the not-so-efficient 5VSB rail. Obviously a previous generation 5VSB circuit was used in this fresh platform, to keep the price tag as low as possible, but I wouldn't mind spending a few bucks (or pounds) more to get higher efficiency.

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Disclaimer: Aris Mpitziopoulos is Tom's Hardware's power supply reviewer. He is also the Chief Testing Engineer of Cybenetics, and developed the Cybenetics certification methodologies apart from his role on Tom's Hardware. Neither Tom's Hardware nor its parent company, Future PLC, are financially involved with Cybenetics. Aris does not perform the actual certifications for Cybenetics.

Aris Mpitziopoulos
Contributing Editor

Aris Mpitziopoulos is a contributing editor at Tom's Hardware, covering PSUs.