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M726 BIOS UDMA-2

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First post, by mmax

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From time to time I revisit my old enemy, the PCCHIPS M726 board.

This ia a very bad board due to the fact, I still can't pinpoint the issue that you cant have AGP and 100MHz FSB working reliably at the same time.

As I read this article
https://web.archive.org/web/20070210065817/ht … w-software.org/
I have tried it.
The chipset settings haven't done anything good. They made my PC crash/freeze.
But the UDMA settings were working. So I decided to put them into BIOS as they should be. With the help of LLM.

So there is now and option to use UDMA-2 mode if the drive supports it. It ask the drive if it supports UDMA-2 and if yes then it uses it.

The attachment M726-BIOS-UDMA.jpg is no longer available

Benchmark with UDMA-2 disbaled:

The attachment without-udma2.jpg is no longer available

Benchmark with UDMA-2 enabled:

The attachment with-udma2.jpg is no longer available

Here the BIOS with all the documentation LMM provided:

The attachment M726_UDMA_CDROM_DMA_BIOS_Kit_BETA16.zip is no longer available

Form time to time I am trying to investigate the issue with AGP and 100MHz FSB, but no luck yet.
I tried to set AGP registes differently, tried to use different drivers or no drivers for the Ali chipset, different OS (Win98SE,WinME), disable sideband for AGP, different CPUs, different AGP cards
Sometimes it looked I can make it work without the drivers or with disabling sideband, but that was just and illusion.
Someone mentioned it is the power management of the board, but I dont know...

I someone know how to make it work both AGP and 100MHz FSB at the same time, I would appreciate if he/she can share.

Reply 1 of 3, by pyrogx

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Does AGP work with 66MHz FSB?

Reply 3 of 3, by pyrogx

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Just a wild guess: That's an AT board, so AGP gets its 3.3V from some additional voltage regulator (AT PSUs do not have 3.3V lines). Maybe this regulator is too weak to drive AGP cards properly on this board.
Still doesn't explain why it works at 66MHz...