# Underclock?

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Folks,

I have a 6-year old Asus A7V133 motherboard with an AMD T-bird 1000,
running at 1 GHz.  It's a nice computer, but the CPU throws off a lot of
heat.  What if I ran it at 900 MHz, or 800?  Would it be substantially
cooler or just a little cooler?  I'd be happy to trade some speed for less
heat, but I have no idea of the relationship between GHz and heat.  Is it
linear?

-  Dave

## Re: Underclock?

'Dave' wrote:
| I have a 6-year old Asus A7V133 motherboard with an AMD T-bird 1000,
| running at 1 GHz.  It's a nice computer, but the CPU throws off a lot of
| heat.  What if I ran it at 900 MHz, or 800?  Would it be substantially
| cooler or just a little cooler?  I'd be happy to trade some speed for less
| heat, but I have no idea of the relationship between GHz and heat.  Is it
| linear?
_____

If it's run six years, then I wouldn't worry about how heat is generated,
unless, of course you don't have sufficient ventilation to keep the system
case interior reasonably cool.  I'd guess an AMD T-bird 1000 would create
about 40 Watts of heat; +/- 10 extra watts is not going to make much
difference in the overall system temperature, and that is about all the
difference that a 100 MHz or 200 MHz speed reduction would make, even if the
CPU core voltage can be reduced also.  (ALL the power applied to a CPU is
turned into heat - save for a very, very, very tiny amount carried out as
data.)

You can use archives from the AMD site to find more exact details.
None of the power/speed/voltage relationships are linear.  In a strictly
resistive load, the power varies with the square of the voltage applied
(double the voltage, the current doubles equaling 4 times the power.  A CPU
is not a resistive load, and also uses more power when a signal state is
switched than when it is steady.  You might be able to find power
consumption vs. voltage and speeds for new CPUs.
| Folks,
|
| I have a 6-year old Asus A7V133 motherboard with an AMD T-bird 1000,
| running at 1 GHz.  It's a nice computer, but the CPU throws off a lot of
| heat.  What if I ran it at 900 MHz, or 800?  Would it be substantially
| cooler or just a little cooler?  I'd be happy to trade some speed for less
| heat, but I have no idea of the relationship between GHz and heat.  Is it
| linear?
|
|
| -  Dave

## Re: Underclock?

I built an XP 2000+ for a friend and a good heatsink wouldn't fit
because of a capacitor close to the cpu socket. So I put on a so-so
heatsink, and it ran a bit hot for my taste. Lowering the fsb from 133
to 100 totally solved it.
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## Re: Underclock?

Thanks to Phil and Ed -- your comments motivated me to check things out a
little.

Following Ed's suggestion I changed the FSB from 133 to 100.  This change
also reduced the CPU from 1000 MHz to 750.  The exhaust air and the case
under the CPU air seemed a little cooler.

I found and installed Asus "Probe" software that takes the CPU's
temperature.  It reported that the CPU is about 56 degrees C after half an
hour at 1000 MHz idle, and about 52 degrees at 750.  I say "about" because
the temps drifted around a little.  Probe reported voltages, too, but they
were the same.

Phil is right, if this computer hasn't burnt up in 6 years, it's not going
to.  But then, I just don't like this computer because of its heat, so I
don't use it much.  I think I'll run it at 100 FSB, and look for better
fans.

Thanks again, guys, for your thoughts.

## Re: Underclock?

That's awful much too hot. That's only at idle and you never want it to
touch 60 because it gets into the zone where it can make little errors.
Best to download prime95 and run the torture test and see how hot it
gets, and whether it makes any errors, or just load it up with something
that uses 100% cpu to see how hot it gets, and first heat the room to as
hot as it will get in summer.

The 2000+ that's now at 1250 just reaches the low 50's at full load.
---
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## Re: Underclock?

Ed,

Right, this thing is too hot.

I posted "Underclock?" to this newsgroup on Monday.  On Wednesday NewEgg
sent me an ad for a Centurion 522 case for \$30, which I couldn't resist.  I
bought it, and it was delivered today.  Looks like a nice case, especially
for \$30.

I'm going to move my too-hot computer into this new case, which has 120 mm
fans.  (I'm using 80 now, front and back.)  I'm sure this will help, but I
probably also need a better heat sink and CPU fan.  I just checked NewEgg
and Tiger Direct -- both still stock Socket A heat sink/ fans.

Then I might try overclocking!

-  Dave

## Re: Underclock?

Dave,

Have fun with your new case.

I would suggest going to the arcticsilver.com site and check out
Ceramique, and the instructions:

http://www.arcticsilver.com/ceramique.htm

http://www.arcticsilver.com/ceramique_instructions.htm

Even if you don't use Ceramique, there are good instructions there.

OK, people, please no paste war.

---
Ed Light

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## Re: Underclock?

Boon wrote:

underclocking/undervolting articles:

http://www.silentpcreview.com/section14.html?from=15

---
Ed Light

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## Re: Underclock?

Ed Light wrote:

The last article's description is mistakenly about a power supply, but
the links to the article work ok.
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## Re: Underclock?

BTW, was that an Athlon 1000? I don't think those are hard to cool.

If it's a 1000, I don't think there's alot of room there.

---
Ed Light

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## Re: Underclock?

Ed,

Thank you very much for the references.  I'm still studying them.  I am
experimenting with lower CPU voltages based on the references, and finding
substantial temperature reductions and so far, no problems.  My CPU is an
AMD Athlon ThunderBird 1000, Model AMT3C.

-  Dave

## Re: Underclock?

Hi, Dave.

Yes, those are neat articles. Glad they're so fascinating!

Sort of off-topic:

It's amazing how great that cpu can run XP, especially with a 7200 rpm
hard disk and enough memory. I upgraded a person's Win ME rig with that
very cpu in it. It just had a little aluminum heatsink, and the temps
were ok, but it had a very loud, fast little fan on the heatsink. It had
128mb of ram, and I added 256. XP starts up using 256, so it was enough.

I did another rig Win 98 to XP that was the Athlon XP running at 1250,
where I had to lower the bus to cool it off.

On both rigs, I ordered the memory online and set up the software while
waiting for it, with only 128Mb installed. That radically inhibited the
one with the 5400 rpm disk, but the one with the 7200 wasn't that bad.
Nice disk swapping. Of course, when the memory came, it was like night
and day.

Both users are really happy.

I'm really glad I imaged their hard drives, though, because one of the
XPs became unbootable. I stuck that hd in my computer and lifted all the
data, then just replaced C: from the image (using bootitng) and copied
the data in.

With the NTFS file system, huge Outlook Express mailboxes open many
times faster than with the old fat32.
---
Ed Light

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## Re: Underclock?

Boon wrote:

I have an XP2500+ Barton that will run at XP3200+ speed at default vcore
(actually at default - 0.05V). It's quite well cooled so heat isn't an
issue. However, for a while there I wasn't doing anything demanding and the
beast was on 24/7 torrenting etc. so I decided to slow it down a bit. I
dropped it from 2.2GHz and 1.60Vcore to 1.5GHz and 1.35Vcore (tested stable)
and it worked well. Not *that* much slower responding (I kept it on a 200MHz
FSB) and significantly less power consumption/heat. I used to have a site
bookmarked that allowed you to input your CPU details, family, speed and
voltage, and give you a 100% consumption figure (in watts) and an idle
figure. (Lost the URL). The drop I did with mine reduced the CPU power
consumption (and heat production) by 50%.
--
TTFN.

Shaun.

## Re: Underclock?

Boon -- how did things turn out? How's you new case?

---
Ed Light

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## Re: Underclock?

Ed,

Sorry for the delayed reply -- I haven't visited this newsgroup in a
while.  The new case works fine.  I'm still using the underclock settings
I mentioned on August 16, running a 1 GHz Thunderbird CPU at 750 MHz.
The result is a very cool system that I use regularly.  The CPU gets up
to about 49 degrees under heavy use.