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T4X CPU undervolting database

T4x series specific matters only
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T4X CPU undervolting database

#1 Post by ziemeck » Thu May 17, 2018 11:07 am

Some of us still use T4X either due to sentiment or as a silent typewriter. I am using a T42 (15' XGA) for www programming using Eclipse (javascript, php) - and with 2GB of RAM it still gets the work done after 14 years in service. After I recently disassembled and cleaned up CPU cooler (second time since the purchase!), applied motor oil to fan sleeve bearing I decided to make it even more silent, using NHC to undervolt CPU.

Methods used to find stable voltages:
1. find lowest voltage that passes NHC test
2. test the voltage for stability in real life applications: running firefox, playing 15-20 mins of youtube videos (max 720p), using Eclipse, playing music (in my case every NHC "stable" voltage above multiplier of 6 required a 1-step-increase of voltage to run stable in all my applications)

The voltages stipulated below are stable for my particular CPU and my particular motherboard. Please use these as a starting point for your tests rather than a ready answer.

My CPU is a Dothan 1.7 (fsb 400MHz), my motherboard is one with dedicated ATI GPU: Radeon 7500
Lowest stable voltages:
Model: T42, CPU: Dothan 1.7 (Pentium M 735), Motherboard specs: Radeon 7500
Multiplier	Voltage
6		0.700
8		0.732
10		0.796
12		0.860
14		0.940
17		1.068
Please share your undervolt settiings below, this might help some oldtimers silencing their T4Xs
Need to replace T60 LCD? Read this thread.
High-pitched fan noise [viewtopic.php?f=29&t=86763]?
- Sure the fan [viewtopic.php?f=29&t=74322]?
- Fan lubrication [viewtopic.php?f=29&t=87448],
- Fan replacement/reapplying thermal grease [viewtopic.php?f=29&t=80203].

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Location: Toronto, Canada

Re: T4X CPU undervolting database

#2 Post by kfzhu1229 » Tue Aug 21, 2018 9:14 pm

Well about a year and half ago I did an inquiry about the undervolt settings for a Pentium M 780 on a ThinkPad T43/p.
In short, the following settings worked for many other users and also all of my 3 Pentium M 780 CPU's and their respective motherboards.
6x 0.7V
8x 0.796V
9x 0.828V
10x 0.892V
11x 0.972V
14x 1.084V
15x 1.116V
17x 1.228V
And these settings are provided but untested, thus entering the silicon lottery area:
Multiplier 6 - 0.6

8 - 0.78

9 - 0.812

10 - 0.876

11 - 0.956

12 - 1.004

14 - 1.064

15 - 1.120

16 - 1.2

17 - 1.224
T23 PIII 1.13ghz 1gb W7
T43 15" 1.86 XGA 2gb fp W7
T530i 15.6" i7 16gb fp W10
Flexview UXGA:
A30p PIII 1.2 1gb W7 (IDTech)
T43p 2.26 2gb fp W10

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