引用自
http://www.playtool.com/pages/psuoverload/overload.html
The ATX spec defines the use of each 12 volt rail for dual 12 volt rail ATX12V PSUs. The two rails are called 12V1 and 12V2. 12V2 is used to power the CPU through the 4 pin 12 volt power cable. 12V1 is connected to every other 12 volt cable. At least that's the standard. Not everyone obeys it. As far as I know, all dual 12 volt rail PSUs connect 12V2 to the 4 pin 12 volt power cable. And most PSUs connect the 12V1 rail to all their other power connectors. But some PSUs apparently use 12V2 to power some cables which according to the spec are supposed to be powered by 12V1. Unfortunately, they usually don't tell you which power connector is hooked to which rail.
簡譯一下:
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