Slowdown cpu speed software prototype tool for VIA based VT82C596A southbridge motherboards \ VOGONS

Slowdown cpu speed software prototype tool for VIA based VT82C596A southbridge motherboards

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First post, by Upuaut

Posted on 2026-06-07, 19:51

Upuaut Offline

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Joined: 2026-06-07, 19:24
Location: Denmark, Herning

A few days ago, I tested my motherboard with a software tool that works with the VIA 596A chipset by manipulating its power management registers. Sinse the 596A chip is a Mobile PCI Integrated Peripheral Controller (MPIPC) I discovered the ability to control the overall system speed on my tested motherboard, a Matsonic MS7101C with Intel Celeron 400Mhz CPU (66.6 x 6.0). So I want to share the results I got with the community.

Reply 1 of 3, by rasz_pl

Posted on 2026-06-08, 13:33

rasz_pl Offline

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Looks like it mostly throttles IO or maybe bus.

https://github.com/raszpl/sigrok-disk FM/MFM/RLL decoder
https://github.com/raszpl/FIC-486-GAC-2-Cache-Module (AT&T Globalyst)
https://github.com/raszpl/386RC-16 ram board
https://github.com/raszpl/Zenith_ZBIOS Zenith Z-386 MFM-300 ZBIOS disassembly

Reply 2 of 3, by Upuaut

Posted on 2026-06-13, 08:03

Upuaut Offline

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Rank: Newbie
Posts: 3
Joined: 2026-06-07, 19:24
Location: Denmark, Herning

Here is the code. Its not a final version still working on it. Works thrue chipset PCI registers.

Reply 3 of 3, by Upuaut

Posted on 2026-07-16, 19:44

Upuaut Offline

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Rank: Newbie
Posts: 3
Joined: 2026-06-07, 19:24
Location: Denmark, Herning

may be it need a bit of explanation. I have a retro DOS machine based on that celeron 400, and some games is hate this high speeds, slower machine I don't have, instead I can write some useful code. That's what that.

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