The BX chipset is faster and more stable. It's one of the best chipsets Intel ever did.

You will have absolutely no practical benefit from going with the BX board over LX with a 66MHz FSB CPU aside from AGP 2x which likely wont matter with the CPU bottleneck. It alao has ECC support if you use that I guess.

Probably better to use the P2B for a faster build, the 233 is well suited to the LX chipset - my current favourite PC (because of integrated OPL4) has an LX chipset motherboard, it came with a PII 233 and works pretty well overall.

The P2B might have better options for underclocking / disabling cache though, so check the manuals for each to see if they allow disabling L1 / L2 cache, or just disabling all cache.

That is what I was looking for....

Still debating though as I have no plans to do that right now as I am trying to keep the number of running, built retro PCs down to 5 or 6 core machines that have best performance I can do on each, but who knows if I will get the urge to build something between the 233 and my 1.266 P3 machine....If I don't build anything else between them then using the P2B would be the best build for the 233 for maximum performance.....but knowing myself, once this is built I'll want to build something else!

The underclocking features are something I didn't think about though. Will have to look over the P2B and gigabyte manuals to see what they can do

That's the nice thing about slot1 - especially BX boards that can set multiplier / FSB, it can with suitable bios support, handle processors from the P-II 233 up to the coppermine P-IIIs, and they're easy to swap out.

Also, some of the older Intel CPUs are unlocked, so can be underclocked via multipliers, which is discussed here, with the P2B: Quick question about underclocking a Pentium 2
edit: and here Which Pentium IIs can be underclocked?

Appreciate the links