Hardware Question - A7N8X oddity

[kas]

On Sat, 2005-06-11 at 02:05 -0700, Michael A. Peters wrote:
> On Fri, 2005-06-10 at 23:06 -0500, Dave A. Marquis wrote:
> > Sounds like a dieing cmos battery to me.....
> 
> It's a CR2032 which seems fairly cheap - I'll try that first.
> I hope that's it.
> 
BIOS has determined that your system won't run properly at the full
rated front side bus of the processor and has throttled it down to 100
mhz rather than the desired 166 mhz.  Possible reasons for this
happening:

1. CPU is running hot, probably because the heat sink/fan is covered in
cruft.  Clean throughly.  Removal for cleaning is *not* recommended
unless you are experienced as you can kill an Athlon in less that 10
secs if the HSF isn't reinstalled properly.  Look to the net for
instructions if you feel removal necessary.
1a. CPU is running hot because the heat transfer compound or phase
change gook between the CPU and HSF has gotten old and is acting more
like an insulator.  Athlons don't have a heat spreader so a good thermal
interface from the chip to the HSF is mandatory.  I use Arctic Silver (a
small tube is practically a lifetime supply) but there are even better
things these days. Don't remove the HSF if you don't have fresh compound
on hand. 

2. Passive components on the motherboard have aged and have dropped the
actual Vdd that the processor is seeing.  The fix is to adjust Vdd in
BIOS upwards by .025V. The setting is usually on auto but the bios logon
screen or the bios health screen may tell you the current setting.
Don't do this until making very sure the problem isn't 1 or 1a as this
will just add to the problem the if the CPU isn't being cooled
adequately.

3. DIMMs are getting old and lazy.  Tune them up by adding another 0.1
Vdd or if on auto, try 2.6v which won't stress the DIMMs much.  If
neccessary, 2.75v won't kill the DIMMs but may shorten their lives
slightly but, as they are basically obsolete now, who cares ;)

4. If there is active cooling on the north bridge, the same things as in
1 and 1a apply.

5. The +12V section of the PSU has gotten marginal.  These things want
very clean +12 to the CPU voltage regulators and use it in large
quantities.  Asus generally use 2 phase VRMs so it is even more critical
with them. If the PSU's spec is 26A or less and it is getting old, it
may just not be up to the job any more. 

Generally speaking, gkrellm and lm_sensors is your friend here.
Installing both to monitor voltages, temps and fan speeds is well worth
the effort.

HTH,
Karen