jason str said:
lets say for instance we are talking about a single rail psu to make things easy. Multi rails seem to confuse people.
Does the 3.3v and 5v lines run off of the 12 v rail or a seperate circuit ?
Im also having issues about people using watts to convert power draw i dont understand what they are talking about. I have always used amperage to measure current draw.
Does anyone have a detailed schematic of a single rail psu to post here for reference this would make understanding the circuitry much easier. I have looked around but cant seem to find any.
Just ask a manfacturer, for schematic .
Main circuits used in modern system are +5V & +12V. Look at cabling from PSU, Red is +5V / Yellow is +12V and Blacks are ground (There is 5 & 12 grounds)
The mainboard uses the +3.3V rail
The main advantage of single +12V rail, is the amperage is set rate. There are xx amps to supply system.
With more than 1 +12V rail, the amperage is still xx amps, but can be split.
Example:
+12V Rail 1 = 25Amps

+12V Rail 2 = 25Amps
Combined total amps is 30Amps for both rails...........(smalll print)
So if graphics card needs 22Amps on the +12V rail & CPU needs 8Amps, what is left for other devices like fans and hard drives etc.....
Some quality PSU's will boot OK, but you will lose performance and over stress all components in system.......which shorten component life and cause problems with software..........
Hence why I use, a single +12V rail psu or a dual channel with lots of AMPS on the +12V rail