Due to several requests, I will be including internal pictures and discussion of each Power Supply. I want to warn each reader that opening up a Power Supply can be very dangerous and will instantly void the warranty of that unit. That said, many find it comforting to know the possibility exists to adjust different voltage rails should the need exist. I will say that all testing was done prior to opening these units and NO voltage "tweaking" was performed on any of the units OTHER than the older regular ATX Fortron 520W Power Supply used for comparison, which I had previously adjusted to higher voltage levels due to fluctuations on a P4 setup.

Zippy HP2-6460P



As seen above, the Zippy HP2-6460P is quite beefy inside and does have adjustable pots. Some are well hidden underneath wiring so adjusting them may prove difficult. Overall, internal construction is excellent and top notch parts used throughout.

Zippy PSL-6701P



The Zippy PSL-6701P is packed full of the fine components. The transformers are huge as are the heatsinks. Definitely, I would call this unit overbuilt, which is just how I like my computer parts. Internal adjustable pots are included for those inclined to mess with them. However, I really don't know why you would need to as in the several systems I have had this unit in; I have never ever experienced any low rails or significant fluctuation of voltages.

Silverstone ST52F



The Silverstone ST52F is well built and high quality components are used in construction. Adjustable voltage pots are readily accessible; however pay attention to the red wax/paint markers. If adjusted, this would break the "seal" on each pot and the manufacturer would know the unit had been tampered with.