Overall, the new Seasonic S12-600 power supply produced very good results.  The unit exhibited good voltage regulation with excellent stability and offers a lot of capacity on the +3.3V, +5V and dual +12V rails.  The S12-600 is very quiet even when operating under a moderately heavy load and runs cooler than most.


The S12-600 uses active power factor correction and produced one of the highest overall efficiencies I have measured to date.  Seasonic is to be congratulated for developing a line of power supplies that are both environmentally friendly (active PFC) and highly efficient (>80%).


On the down side, the main output voltages were a bit low when using the 24-pin to 20-pin ATX adapter cable.  Even so, all measured voltages were still within the required ATX12V specified tolerances.


One feature that may appeal to some is the cable management kit labeled Dr. Cable.  The included cable ties are a welcome addition, which I use regularly.  The spiral wrap on the other hand just doesn’t work for me — I prefer the more elegant, but harder to install nylon web looming material.  Spiral wrap is easy to apply but the finished result is not as clean.



  • 600 watt combined load (continuous, not peak)
  • Good DC voltage regulation (all rails within spec)
  • Active power factor correction (PF = 0.99)
  • High efficiency (>80% with typical load)
  • Auto voltage select and Power On-Off rocker switch
  • Very quiet during normal operation (<35 dBA)
  • Lots of peripheral drive connectors
  • Backed by a 3-year warranty


  • Using the 24-pin to 20-pin adapter slightly reduces the primary voltages
  • Expensive (however, higher efficiency will pay for itself over time)


I would like to thank our friends at Seasonic for sending us the S12-600 to review.  Check out one of the new S12 series power supplies the next to time you are ready to build a new system or upgrade an existing one.


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