The box talks a lot about the solid state capacitors used on the 12V rails - probably something that's going to be a mystery to most home users. The advantage of solid state capacitors over electrolytic capacitors is not only that they last significantly longer but they also operate slightly better and run significantly cooler - something we all know is crucial in building a high performing and silent power supply. Make sure you don't misunderstand the box though because the solid state capacitors are only on the 12V rails - not the entire power supply!

The cabling on the S12II power supplies is all hard-wired, not modular like most power supplies these days are. This does have it's pros and cons however. Most people dislike modular power supplies because of the added resistance they offer. Having a modular cable on a power supply adds a comparable amount of resistance as if the cable were two meters longer on a hard-wired power supply! Thus by eliminating the modular connections and having all the cables hard-wired, you can essentially have better electrical performance for the money. The downside to this is that you now have a large clump of cables in your case and hiding all the unused ones, while still trying to maintain good airflow, can be tricky in smaller cases. I've included a diagram below from Seasonic that explains the connector layouts on all the S12II series of power supplies.

I'd also like to make a quick mention of Seasonic's warranty for this power supply. Any of their retail power supplies manufactured after November 2007 now come with a 5 year warranty! Compared to most manufacturers who offer between one to three years warranty, this is certainly a huge plus to have five years and also an extra piece of mind for your system.

Installation:
Installation was a breeze for me, since the S12II is a standard PSU size and not really long like some, it should easily fit in any case out there.

Testing:
I used the same method to test the S12II as I do on any power supply. The voltages were first recorded with the system at an idle stage and then again after it has been at a stressing 100% load for 30 minutes.

Testing System:
CPU: AMD Athlon 64 3200+ (Socket 939) @ stock speeds
Motherboard: Biostar NF4UL-A9
Memory: 1gb (4x256mb) PC3200 400mhz
HDD: Western Digital 160gb SATA II (WD1600JS), Seagate 250gb SATA II
Video: Asus EN7600GS Silent
Sound: Mark Of The Unicorn 8PRE Firewire Audio Interface
Power Supply: Seasonic S12II 500W
OS: Microsoft Windows XP Professional SP2

Performance of the S12II 500W proved to be excellent. I saw on very very minor voltage fluxuation during testing, so little that it was only 0.01V that seemed to change on all the lines except the +12V which was 0.05V difference. Having voltage stability like this is a dream for those running powerful systems and/or those who do intense overclocking which can sometimes push the power supply much harder than the system would while running stock.

Noise level was another big category I looked into while testing. With being as well known as this power supply is for being quiet, I had to witness it myself before I could believe it! To say the least, I was incredibly impressed right from the moment I first powered my system up. Having a silent PC myself, when I can't distinguish the power supply from any of the other silent fans I'm running, that is a good thing! Even throughout full load it still remained quiet, I didn't even really notice any huge changes in fan speed. The only way I could actually pick out the noise from the S12II's fan itself was to put my ear right up to it - now that's quiet!