I think with Pentium class motherboards you can't OC the ISA bus. That's why you get lower score than 486DX with ISA cards - even though you have slow ISA cards.

Yeah I sure have slow ISA cards.. 😁
Better are expensive and actually my Ati wonder xl is the best I have. But one thing I like is the building quality of the card for design and components. I would like to find some other video card fast ok, but with high quality layouts.