Erk, I gave up on my VIA Intel board, with respect to Coppermine performance. (Acer S61 board) And given that the 3rd PCI slot is not working correctly, I figured I had wasted enough time on this board.
Worked fine if I plonk a Katami or order CPU in it, gave expected performance. Ran a bit slow if I put in a coppermine CPU.
Additionally, stop trying for 4x AGP on this board, you will only ruin stability. The 4x AGP on these boards is only barely functional, and will usually crash if you try to use it. AGP 2x is usually stable and fast enough. 4x AGP was one of the market points at the time, rather than an essential performance feature then.
That said, the performance issue that I was having probably isn't universal to all VIA Intel chipsets of the era or all motherboards that use them.