View Full Version : -5 Volts question and High CPU temp

08-04-2002, 02:44 AM
Rebuild questions:

rebuild incorporating Biostar M7VIG mobo / Duron 1200

I installed AMD supplied HSF & required thermal pad.
CPU temp 55C to 58C seems high to me considering that usage has been only moderate. Temp per bios during first boot is 47C. Temp in the shop is 75F average. I have installed two additional case fans to promote good cooling.
Adjacent Athlon 1200 system runs in low 40's.
I have Arctic Silver and am considering reinstalling HSF using it, and damn the AMD warranty.
The system will be used in 72-degree room, and will be used only for word processing and email, but I wish to avoid the wrath of my loving wife if it starts to act up for her.
There is not a HSF available which will cool the wife if I replace her working PC with a problematical one.
Any ideas re keeping down both temperatures appreciated.

ATX Power supply question:

What is 5V used for, and will 5.7V (as shown in HW monitor) transform my case into a miniature crematorium?
I replaced the suspect PS, but am reluctant to scrap it until I obtain further information.

Quote from PC Guide follows:

"-5 V: A now archaic voltage, -5 V was used on some of the earliest PCs for floppy controllers and other circuits used by ISA bus cards. It is usually provided, in small quantity (generally less than 1A), for compatibility with older hardware. Some form factor power supplies such as the SFX no longer bother to supply it (systems using the SFX power supply are intended not to have ISA bus slots)."

As there are no ISA slots on my mobo, and no old hardware in system, it seems that the PS is usable.

What think you?

08-04-2002, 03:51 AM

Welcome tohttp://www.pcguide.com/ubb/pcgubb.gif Forums!

My contribution would be to suggest lapping the heatsink. The last two builds I did with out of the box aluminum heatsinks proved to be high exactly where the die would mate. It appears that the extruded aluminum must cup when cooling.

If you've access to a machinists granite stone you can pull them down to a near mirror finish with over the counter sandpaper. I begin with 320, then 400, 600, and finish with 1500. Our Moderator mjc was correct that it would bring my temps down...along with the Artic Silver.

It took on the average 1/2 hour per heatsink. Temperature drops were a little over 3C at idle. If you upgraded to say a Thermaltake Volcano 7+ I suspect you'd also see an improvement in temps.

08-04-2002, 07:47 PM
Some BIOS systems give a reading on the high side
of things.

All in all the readings you have are not out of line
using a Duron chip and an AMD retail Heatsink/Fan.

Can only pass along the course I normally take. The
AMD retail Heatsink goes back in the box it came in with
what is left of the thermal pad still on it. Clean up
the CPU chip-die with pure acetone. Install a very small
amount (evenly) of arctic silver on the chip-die and
install a HSF such as a Thermalright AX-7.

As far as the PSU if the +3.3v and +5v sides remain steady
and strong you are good to go.

Here's a Link to a review on the AX-7.


08-04-2002, 11:04 PM
Thanks to you both for the good information.
The two identical heatsinks (am building a backup system too) were both cupped about .005 in.
I lapped the stock HS, and after using 600 wet or dry, found weird grainy streaks in the extrusion that were not from sanding. I am going to replace the HS with an aftermarket unit, maybe the one suggested by ranchdog.
In the meantime, I reinstalled the stock unit and the temps dropped 3-4 degrees C.
thanks again!

08-04-2002, 11:09 PM
I was rather suprised that my Volcano 7+ copper sink was also cupped...had to pull it down also...

08-04-2002, 11:52 PM
the Volcano 7 is under consideration. How noisy is it when maxed out?

08-05-2002, 12:03 AM
Good question Juan, I'm running it with the switch in the center position and it's not bothering my wife...or she'd be bothering me! :(

I'll have to crank it up and see how it does full throttle (will let you know). I'm running the 7+ ...however, I was just talking a look at Thermaltake's newest the Volcano 9 with the thermister that mounts to the underside of the processor. It's about the same price and you might want to check the specs. I seem to remember that it was pushing about the same CFM at 4800 RPM as the 7+ does at 6000...

I haven't tried to mount the switch for easy access. I've just been leaving it inside. This would speak to the upside of the "9" because it's variable speed is heat regulated as needed!

Would be interested in your appraisal if you take the time to compare the specs! ;)

08-05-2002, 12:29 AM
Weird grainy streaks?

Sounds like that heatsink had some slag in the middle...not good.

Oh and here are a few suggestions about the wife's temp....

1. Chocolate

2. Roses

3. Dinner

4. ;)

08-05-2002, 12:51 AM
mjc, hehe :D:D:D

08-05-2002, 02:38 AM
I checked out the Volcano 9, and it seems to be what is needed to avoid becoming a casualty of the wife's version of Mount Vesuvius.

Chocolate and flowers are regularly on my shopping list. I figured that having a duplicate backup PC for her would save $$$$$$$$$$$$, and reduce chances that I'll end up in a full body cast!

thanks for the help!