Power supply volts

About where is a good level for the +12v rail? I'm assuming within a
percent or two is good.
My 400-watt CompUSA power supply is getting between 11.904 and 11.968. I'm
using an Ati x1600 AGP 8x video card, which requires an extra 4-pin molex
connection from the power supply. The +12v was the same before I got the
video card. My +5v is getting 5.053, my +3.3v is getting 3.344, and my
VCore is getting 1.392 to 1.408 (I have a Sempron 64 2800+).

In article <__x5g.130391$oL.29036@attbi_s71>, "Travis King"
<Anonymous DeleteThis @none.com> wrote:

> About where is a good level for the +12v rail? I'm assuming within a
> percent or two is good.
> My 400-watt CompUSA power supply is getting between 11.904 and 11.968. I'm
> using an Ati x1600 AGP 8x video card, which requires an extra 4-pin molex
> connection from the power supply. The +12v was the same before I got the
> video card. My +5v is getting 5.053, my +3.3v is getting 3.344, and my
> VCore is getting 1.392 to 1.408 (I have a Sempron 64 2800+).

If you check the side of the supply, you are allowed 5% variance.
If you check the voltages with a multimeter, in many cases the
voltages are pretty close to the required values. The monitor
chip on the motherboard is not a "perfect voltmeter". Your 12V
is within 1%, and that is excellent. You can sleep well tonight.

Vcore is created by a circuit on the motherboard, so the
motherboard is responsible for the voltage value. The
processor specifications have a "load line" with "droop"
designed in - the voltage is allowed and is expected to
drop when the CPU runs at 100%. So do not be alarmed if
you see the value change when you put a load on the
processor. In round numbers, the voltage may be allowed
to drop by 0.2V at full load, just to give you some idea
of what a big drop would be.

Since AMD has Cool N' Quiet, the VID (voltage ID) pins
are dynamic, and can be programmed on the fly. When there
is little load on the processor, Vcore can be commanded to
drop down to 1.1V or so. If you see values like that,
it means your processor is conserving power for you.
Again, nothing to be alarmed at.

And, what that means, in summary, is you have to know
what your processor is doing (busy or idle), to know
whether the voltage happens to be too low at a given
point in time. If the processor is busy (running Prime95
for example), and you measured 1.1V for Vcore, that would
be bad. If Windows was idle, then seeing a reading of
1.1V would not be so bad, because CNQ turned it down
on purpose, to keep things cool. If I had a processor
like that, I probably would not bother looking at the
measured value, unless the machine was crashing all the
time.

Paul