A 486, especially faster model deserve fast bus speed. Guess why VLB appeared on 486s ? ^^

ISA is for 386s and lower. Even a TSeng ET4000 AX on ISA is twice as slow as VLB video card (except if I oc ISA way out of spec, but I doubt running ISA cards that fast is safe anyways xD).

And this chipset have a great implementation of PCI so it should perform well. Actually I have a motherboard with that exact same chipset (running an AMD 5x86 (aka 486 DX5)) and well it's nice.

However you might want to have another video card, SiS never did fast video chipsets.

PCI, if it were something like a 486sx-25 you might not see much difference but a DX4-100 can make good use of the extra speed in more demanding dos games.

Make sure you clip/desolder out the battery if it's not the now-standard coin cell type. The "barrel" batteries leak and can damage the motherboard.

PCI it is. I have:

Riva128 4mb PCI
Matrox Millennium PCI
Matrox Mystique PCI
S3 Virge DX PCI
Matrox mga mil-2b is-storm r2 PCI
Cirrus logic gd5446bv PCI

Maybe the Millennium more time correct still high end? The riva128 seems too much without win95.

The battery is the modern ones. Finally after all the problems i had with the old ones...

Well the riva 128 is too new indeed, as for the rest, I guess you can pick the one you prefer/that is the most compatible. I'm not sure if there'll be much difference in their performance (maybe some benchmark will show the opposite ?)

The Matrox Mystique is a great card for a 486. Using that combination as well.

I imagine the Matrox choice will be a good one.
For windows 95 instead which 2d/3d combination would you choose? I have a Voodoo1/2 PCI, also a Matrox M3d even if it will need a much faster cpu just like the Riva128 will need.

Still the Matrox Mystique. It runs the 3d games which have sopport for it very well on a 486. A Voodoo1, 2, m3d and the like are more or less useless with a DX4-100.