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Vcore voltage regulation - XP2200 1.65v/nforce/2-phase

My system is generally stable, but nonetheless crashed after 3 days of continuous operation.  It was an interesting crash because on starting an application, the monitor turned off and the system became unresponsive.  When I tried to reboot after a hardware reset, the system either failed to load windows and re-started, I got a blue screen with a grey box in the middle - almost a BSOD but not quite.  I succsesfully booted into safe mode and removed the drivers for the video card and managed to re-install them which solved the problem.  Looking into it I noticed that the vcore voltage regulation was a little ragged.  I've run a monitoring program for a little while and here are the reuslts:

+---------------------------------------------------------
|Total number of readouts: 21406   CPU Speed: 1804 MHz    
|Running from: 21/02/03 03:34:31   till: 21/02/03 10:26:02
+--------------------+--------+--------+---------+-----

Sensor               |Current | Low     | High    | Av.

+--------------------+--------+---------+---------+-------
|CPU Temp            |54 C   | 50 C   | 60 C   | 54 C
|PSU temp            |37 C   | 34 C   | 43 C   | 37 C
|Chipset             |35 C   | 33 C   | 36 C   | 34 C
|Core 0              |1.65 V  | 1.55 V  | 1.74 V  | 1.64 V
|Core 1              |1.66 V  | 1.63 V  | 1.73 V  | 1.68 V
|+3.3                |3.31 V  | 3.25 V  | 3.47 V  | 3.34 V
|+5.00               |5.08 V  | 5.03 V  | 5.11 V  | 5.07 V
|+12.00              |12.28 V | 12.16 V | 12.34 V | 12.25
|-12.00              |-11.86 V| -12.03 V| -11.78 V|-11.90V
|-5.00               |-5.29 V | -5.39 V | -5.24 V | -5.30V
|CPU Fan             |4623 RPM| 4383 RPM| 4687 RPM| 4545 R
|Exhaust Fan         |2616 RPM| 2576 RPM| 2616 RPM| 2599 R
|CPU0                |100.00 %| 0.00 %  | 100.00 %| 99.92
+--------------------+---------+-------+----------+-------

p26 of the AMD white paper specifies that the maximum permissable "spike/trough" of voltage is:

+150mv / -100mv

with a maximum transient time of 10 micro-seconds.

The normal range should be within 50mv of the rated chip voltage.

My Vcore is rated 1.65V it should stay between 1.60 and 1.70V. The motherboard monitors isn't sensitive enough to pick up transient (>1s) spikes so it's difficult to say wether they stay within spec.

Vcore tends to fluctuate every second, sometimes up to 0.03V at a time.

It may be that I'm barking up the wrong tree as to what corrupted my video card drivers, so I'm open to suggestions.

System:
=======

MSI K7N2-L
nforce2 chipset
Enermax 350W PSU (3.3V + 5V - 185W combined)
                 (12V rated over 18A)
Leadtek Geforce 4 ti4200
1 stick of 256MB crucial pc2700 cas2.5 DDR
FDD
Hitachi 8xDVD ROM
keyboard and mouse
USB webcam
On board LAN + Sound
Belinia 10 60 30 monitor
IBM 180 GXP HDD
IBM 75 GXP HDD
2 system fans
2 PSU fans
1 Procesor HSF
floppy drive

Microsoft Windows '98
Running...
United devices program
Colourific
Logitech webcam software (image studio)

"Winfox" - leadtek 3dfx software.
This utility turned my monitor off, so I ctrl-esc'd out of it and tried
"powerstrip" - another graphics card utility - opening this app killed it altogether.

Everything was running at stock speeds.
Avatar of frache
frache

About your crash :
It's could also a software/OS problem ...
Boot in MSDOS mode and run this command :
scanreg /fix
This command repair the win98 registry.

Change for a new OS like Win XP Pro SP1 could be also a good way ... it's more reliable than a Win98SE or ME.
could be dirty power, try getting a UPS that also conditions the power (or just a plain old power conditioner).  The way your power is jumping around could be a problem.
Wobbling voltages like this are pretty common, and I would be extremely surprised if such a thing were to cause software corruption on your PC--I mean, my PC at home continually runs out of spec on the 3.3V line (it usually hovers at around 3.05) but I've yet to encounter a problem. (Note this machine is running 24/7 at 100% CPU utilisation due to crunching SETI units, so if there were a problem I think I'd have noticed by now!).
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ASKER

The way that it crashed lead me to believe that the problem was possibly hardware related.  Yes the registry/drivers were corrupt : as re-installing the drivers was the solution to being unable to boot.  I've got a plain belkin surge/spike protector but nothing as fancy as UPS.

I really wouldn't mind if my 5V or 3.3V or 12V were wobbling a bit or up to 5% under spec but I find it unusal that the core voltage, which is controlled by the motherboard via a 2 or 3 phase system by most manufacturers at present for AMD based systems is so variable.

I would expect an almost static vcore at -/+ 0.5mv.

Thanks for your comments, frache & Duncan, I'll leave this open for a little longer
The way that it crashed lead me to believe that the problem was possibly hardware related.  Yes the registry/drivers were corrupt : as re-installing the drivers was the solution to being unable to boot.  I've got a plain belkin surge/spike protector but nothing as fancy as UPS.

I really wouldn't mind if my 5V or 3.3V or 12V were wobbling a bit or up to 5% under spec but I find it unusal that the core voltage, which is controlled by the motherboard via a 2 or 3 phase system by most manufacturers at present for AMD based systems is so variable.

I would expect an almost static vcore at -/+ 0.5mv.

Thanks for your comments, frache & Duncan, I'll leave this open for a little longer
I've solved the issue, and if anyone can give me the right answer then you can have the points.

Problem: VxD corruption after 36 hours.

Hint: Nothing to do with power or operating system.
I had a motherboard with a short, and the supply was able to put out enough current to overcome it. The voltage drifted, and the system eventually failed. Only then was the motherboard short found.
ASKER CERTIFIED SOLUTION
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Computer101
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What was the solution?
Ah sure, nrduncan.

The problem was the bios default settings and my type of ram.

It was a peculiarity with the bios.  I mentioned that I used a stick of crucial pc2700 at 2.5 latency using the default bios settings.

By default, FSB is 133/133 DDR, but going into the bios I noticed that it had set the cas latency by default to 2.  Although it ran everything fine for a while, it's not within spec for this DDR ram.  Interstsingly, as soon as I change the CPU fsb to 136 it knocks the latency down to 2.5!

By changing the cas to 2.5 I have run this setup for 5 continuous days without a hitch.

Although UPS is a possible solution, our power isn't normally that bad, and I've run systems for weeks without ups where I am in the uk (depending of course on the weather!!!)
You might want to keep the question as a PAQ rather than delete it, then--someone else might find the answer useful. The mods will still refund your points, so you don't lose anything by doing this.
Yes, good idea.  I'll ask the moderator to change the title to MSI K7N2-L display problems.
Kingsize,
We don't change the titles to questions and generally don't modify much (except foul language, cracks, keycodes, etc) in any question and particularly in those that are finalized).  Members searching the PAQ for MSI K7N2-L or derivations thereof should be able to find this question as this text is posted in a remark.

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