Underclock PIII/Celeron using pinmod?

All about them.

Moderators: NeilBlanchard, Ralf Hutter, sthayashi, Lawrence Lee

Post Reply
kentc
Friend of SPCR
Posts: 160
Joined: Fri Mar 03, 2006 11:50 am
Location: Gothenburg, Sweden

Underclock PIII/Celeron using pinmod?

Post by kentc » Tue Mar 18, 2008 12:54 pm

Hello,

I'm setting up a new firewall using an old PIII. But I want to lower the already low power requirements even further and so I've been searching how to accomplish that using pinmodding (no options in BIOS). However this information is getting old and I can't find anything reliable. So dear SPCR members: how can I undervolt and/or underclock this CPU:

Coppermine-128, Celeron 600 MHz, 128 KiB, 9x, 1.5/1.7 V,12.6 W.

Thank you,
Kent

Vicotnik
*Lifetime Patron*
Posts: 1828
Joined: Thu Feb 13, 2003 6:53 am
Location: Sweden

Post by Vicotnik » Tue Mar 18, 2008 1:25 pm

Check the datasheets from Intel for the CPU. In those you will find a description of the pins and a table with the Vcore values. You can then use this information to see what pins to connect.

You will be limited to a few options unless you can somehow isolate some of the pins. But that is usually not a problem. I usually use U-shaped pieces of copper wire dropped into the socket to connect the pins.

I have used this method on a few Tualatin Celerons, dropping the Vcore to 1.05v and the FSB to 66 MHz. The Celeron 600 is not an ideal underclocker since the FSB already is at 66 MHz, but you could probably lower the Vcore a little bit.

kentc
Friend of SPCR
Posts: 160
Joined: Fri Mar 03, 2006 11:50 am
Location: Gothenburg, Sweden

Post by kentc » Tue Mar 18, 2008 2:39 pm

Hmmm. So I found the datasheet at intel (and a german forum with some helpful illustrations), put nailpolish on a pin that ought t take it down from 1.5v to 1.3v. The result, 1w less from the powersocket?!
In the words of Kevin Kline in A fish called Wanda:
"Disappointed!"

:)

Post Reply