btw, setting the PCI to 66Mhz only makes so much of an increase. Remember, it is tied to the south-side bus, which means the max speed of that chip, is the max data through-put of the PCI bus. Just because you move up the speed doesn't change the fact that you have a MAJOR bottle neck. You also are going to have problems with cards that are even designed for 66Mhz, because it's not going to truly give it the full data through-put it is requesting. Video cards are an example. The PCI bus is choking as it is, but increasing it is going to make it worse since it is going to involve errors because of timing issues. If you don't get the PCI synced up exactly like it should, it could choke the cards because it doesn't have Error correcting.

You may also notice components not working. or burning out quicker. Increasing the speed can also increase voltage, which like Overclocking a CPU, can damage it if it's forcing the chip to move faster than it can. there is a reason PCI was left at 33Mhz, and that was because the chips at that time couldn't handle any faster. once they upped the South-Side bus, they could put faster chips. but they had to use chips that COULD go faster in order to make it work.

That's my $0.02