Bill Stinson said:
I have a new Asus A8V deluxe 939 running a 3500+ AMD64
My temperature is always 80C....at start up and after 10 hours...it does
not vary. The inside of the case feels cool to me, no heat
noticable....The cpu is properly plugged into the cpu fan slot...been
checked repeatedly.
Second problem is voltage issues...always is too high presently CPU
voltage is showing 1.475V. I got concerned and replaced a relatively
new power supply with a new unit. No change on the voltage, all are
running too high.
Any thoughts? Suggestions? Perhaps I am worrying over something that
is in the normal range. Could someone let me know please.
Oh yes, 1gig of ram, run cool 'n quiet, 1 case fan plus the cpu fan.
Thanks in advance to replies.
Bill Stinson
The same monitor chip is measuring temperature and the
voltages. It almost sounds like there is a "scaling error"
in the monitor chip's measurements (although that is an
unlikely situation as a hardware error).
Instead of spending money on the new PSU, I would have
purchased a cheap multimeter. The cheap multimeter would
have allowed you to measure the voltage on a disk drive
connector, and then you'd get to see that the +5V and the
+12V are a lot closer to the correct value, than the
monitor chip is telling you. With the multimeter, you can
also measure other voltages on the motherboard, but those
measurements take a good deal of care, so you don't short
something on the board while using the meter probe. For
those kinds of measurements, I prefer to have the motherboard
sitting on the bench, as the computer case makes such work
difficult.
Now, a few words on power and power supplies.
<--- PSU---> <---- Motherboard ---->
--- 120VAC ---PSU--- +12V --------Vcore_regulator --- 1.45V
+5V
+3.3V ------ Vdimm_reg -- 2.5V -+--->
-5V +---------------------+
-12V |
+5VSB +-- More_cores -- 1.8V --->
|
+-- Vagp_reg ---- 1.5V --->
Your ATX power supply is on the left of the diagram. The
power supply produces the six outputs shown in the middle
of the diagram. Even if the input voltage drops to 95VAC,
the power supply outputs remain constant.
The motherboard also has its own power supply circuits.
The Vcore regulator takes +12V, and makes the 1.45V you saw
on your board. The current the regulator can supply is large,
and can be 60 amps at the low voltage. Being a regulator
circuit, even if the input voltage varied from 11 to 14 volts,
the output would still remain a constant 1.45V. (And, that
is why changing the PSU didn't change anything. Unless
the +12V is cutting out completely, don't expect to be able
to see a change in Vcore.)
One thing about Vcore, is it is designed according to a load
line. This allows the Vcore output to drop a bit, when the
CPU goes to 100% load, and is accounted for in the operating
characteristics of the processor. So, a little fluctuation
in Vcore is normal and nothing to worry about. But the
fluctuation should never exceed the values shown in the
processor datasheet, in order for the motherboard to be
compliant with Intel's or AMD's rules.
The voltage for the memory DIMMs and also the voltage for
the AGP I/O, are also supplied from onboard regulators.
Notice how, in the sample figure above, regulators can be
cascaded. The reason for this, is in the case of the
regulator designs Asus likes to use, they use linear
regulation, and the heat generated is proportional to the
voltage difference between input and output (for Vagp, Vdimm,
and for any other chip core voltage supplies). If each
regulator only has a small voltage across it, the power loss
is kept small too. Linear regulators are cheaper to make
than the switching regulator used for Vcore, and that is
why Asus likes them.
Something else you will notice in the above diagram, is the
monitor chip does not measure all important voltages on the
motherboard. Only the familiar ones are measured, and the
others are free to do whatever they want. And, that is where
the multimeter can occasionally come in handy.
There have been cases in the past, where +12V measured much
higher in Asus Probe than it should, and that was likely a
conversion equation error in the Asus Probe software. But,
when all voltages and temperatures are in error, that is not
likely to be a software fault. It is even hard to make a hardware
based fault like that, because if something was affecting
the monitor chip that much, the monitor chip would likely
die from the strain.
If this was my board, first I would visit the private
forums, and see if other people are noting the same
errors in readings. If there are no other reports of
similar problems, I would RMA the board. Before calling
Asus, I would do a cardboard test, which is basically
to run the board outside the computer case, just to see
if the symptoms are reproducible when no case metal comes
in contact with the motherboard in any way. If the readings
are still all high, then box it up and return it under
warranty.
Now, as you didn't indicate what OS you were using, or
what exact program was doing the temp and voltage measurement,
I suppose it is always possible there is an error in the
program you were using.
If the CPU was at 80C, then the first instant you run a program
like Prime95 (torture test), the processor would crash. It
doesn't sound like the real temperature is anywhere near that
high.
The reason for RMAing the board, is so you can get a hardware
monitor that works properly. No matter how crappy the circuit
is at measuring things, it is still useful at giving you
advance warning of problems with voltage or temperature, so
I would still want one that works.
Paul
