The odds are 50:50 - either it will work or it won't 😀 I have my doubts if this will work because of SW1 and mostly SW2 hardware DIP switch settings for CPU frequency and multiplier on the Gigabyte GA-6VXC7-4X mobo, but if you have a dedicated EEPROM programmer, nothing prevents you to try it.

P.S. The south bridge chips seem to be different (VT82C686A vs VT82C686B) and this also will be a problem. Also Gigabyte board lacks any onboard AC'97 codec (this probably won't be a problem).

P.S.2: VT82C686B southbridge supports UDMA-100 mode, while VT82C686A supports only UDMA-66. I have no idea if they have other differences.

I don't think that having the same chipset is necessarily the same everything else, and so it works, I can say that same MB same model and same chipset, but with different SB, it doesn't work, so you should check before all the chips match, not just the chipset.

What PC@LIVE said ! ^^^^

In general: In addition to the chipset itself, there are also circuits for setting the voltage and frequency, as well as a hardware monitor (if any), etc.
Those are non-standardized.
However, it is safe to assume that this approach can be used for 486 and below boards.

zyga64 wrote on 2025-01-31, 13:03:

However, it is safe to assume that this approach can be used for 486 and below boards.

I already did this once with slot 1 boards, but finding a matching BIOS for north bridge, south bridge, I/O chip, etc. is harder than for s.7 boards or older.

The important thing for softmenu is the clock generator.
You'll need to compare the datasheets for both of they're not the same.

The simpler way is softfsb.

If you want voltages too, you'll need to look at the vrm controller.

And both need to be connected to the smbus or it simply won't work.

Oh, I missed that the southbridge chips were different. Thanks for spotting that!

I suppose it would be a good idea to keep the original BIOS on it's own chip and have a separate chip for other BIOS's that I want to experiment with.

analog_programmer wrote on 2025-01-31, 12:44:

The odds are 50:50 - either it will work or it won't 😀 I have my doubts if this will work because of SW1 and mostly SW2 hardware DIP switch settings for CPU frequency and multiplier on the Gigabyte GA-6VXC7-4X mobo, but if you have a dedicated EEPROM programmer, nothing prevents you to try it.

P.S. The south bridge chips seem to be different (VT82C686A vs VT82C686B) and this also will be a problem. Also Gigabyte board lacks any onboard AC'97 codec (this probably won't be a problem).

P.S.2: VT82C686B southbridge supports UDMA-100 mode, while VT82C686A supports only UDMA-66. I have no idea if they have other differences.

686a/b are pin compatible. Most likely registers too with the possible exception of udma6 register settings.
Ata100 is the only difference I noticed.

myne wrote on 2025-01-31, 15:42:

686a/b are pin compatible. Most likely registers too with the possible exception of udma6 register settings.
Ata100 is the only difference I noticed.

Thanks for the confirmation 👍

Duffman wrote on 2025-01-31, 15:00:

I suppose it would be a good idea to keep the original BIOS on it's own chip and have a separate chip for other BIOS's that I want to experiment with.

Yep. Especially if you can't easily flash the chip with the working BIOS.