quick question 'bout cpu and 12v

[Nephilim]

most modern systems, they pull most of their power from the 12v rail right?

i mean like the cpu and shit.

cuz ah lecturer for a hardware/software fundamentals class i was sitting in yesterday (i reach early, i r exempted), say that cpu does pull from 3.3 or sum so...and yet most places i seeing that since p4 days them pulling with a 12v connector (4pin/8pin)

The most recent ATX std saying:

The ATX12V power connector should be placed as close as
possible to the input of the processor voltage regulator. Locating the ATX12V power connector near the
voltage regulator will help to ensure clean power.

page 13, 3.3.2

In addition to the 24-pin main connector, a 2x2 connector (shown in Figure 9) is utilized for +12 V power
signals for the processor voltage regulator.

page 21, 4.1.2

which mentions the regulator itself, that feeds the CPU, so wouldn't that also imply that the CPU is feeding (although by proxy) from the 12V?

I would like to get a little clarification plix.

[Spazosaurus]

Boards of yesteryear, as you may remember, never carried that 4 pin connector, which is a 12volt supply specifically geared for the cpu. The coming about of ATX 2.0 first introduced this connector. Obviously the cpu doesnt use the full 12v...nowhere near that in fact. That's where the voltage regulation circuitry comes in to step down the voltage depending on the cpu and as you know, some biosed allow for monor adjustments of this voltage to increase stability.

Bottom line, the actual voltage comes from the 12v rail which is stepped down to a voltage usable by the cpu.

[Arcmanov]

^ Concurs.

...and the 12V rail is now mandatory for CPU power because of overclocking.

[Nephilim]

yeah i figure that.

i was just reviewing the old ATX stds, the guy was referring to one nearly 10yrs old.

[mailman166]

I think neph needs to teach a class after he grads what u guys thinks

[Kraeoss]

wouldnt be the first time a lecturer teach sh!t lol.... some just don't keep up with the times imo