Here's a guess.. when you go over 146mhz fsb, your agp/pci divider goes from 1/4 to 1/5 so that your pci bus doesnt go too much beyond spec. So basically, at 146mhz, you were looking at 146/4 = 36.5mhz pci, 73mhz agp bus speed while at 147mhz, you have 147/5 = 29.4mhz pci, 58.8mhz agp. The...