Well at 133 MHz FSB your PCI is 1/4 of the FSB and the AGP 1/2: 33 and 66 MHz. Now AGP shouldn't be a problem as most modern cards can handle an AGP up to 89 MHz without problems (me GeForce2 MX seems to like that speed). But you don't want your PCI to get above 40 MHz. So to keep it a little save lets say you take 38 MHz PCI as the max... that will give you safely access to 152 MHz FSB... your AGP is then 76 MHz which shouldn't be of any problem.
My dual-PSU PC is so powerfull that the neighbourhood dims when I turn it on