Why do I need more than one 12V rail?

Another GC...

The second special characteristic is the single 12V rail. In a time when other manufacturers are building up to six 12V rails in their PSUs, Silverstone has come up with a single rail able to pull a load up to 54 amps. If we look to the actual Intel ATX12V specs, it states that there should be no rail with more than 20 amps for safety reasons. That's a fine step but not possible when you listen to the graphics card manufacturers. They ask for up to 30 amps from a single 12V rail which would make every OCP kick in if reached since they lie at around 24 amps. The result would be a shut-down of the PC while running the actual application. With a single 12V rail Silverstone went in another direction. If you have enough power to supply every component in the PC from a single rail, there would never be any problem since the PSU is regulating all the power drawn from just one source.

This might be a valid way to design a power supply, but, even though we don't know what it is, Intel probably had a reason for designing the specifications around a 20 amp per 12V rail limit. Silverstone backs up their design choice by stating that there is no application which could force this kind of power supply to fail. We have not heard of any problems in the field with a single high current 12V rail, and in our tests we weren't able to provoke this power supply into failing. We will make sure to pay close attention to this during the tests.