FWIW, I have two MSI-6309 motherboards (Apollo 133a chipset) with a Celeron 600 and a Celeron 900. The 600 runs fine at 100 Mhz fsb for a nice 50% o/c. The 900 runs stable at 120 Mhz for a 20% o/c. Neither of mine can get close to 133, although overclockers.com data base shows a number of systems that have successfully achieved it with varying motherboards, cooling options and different processors. Mostly 800's through 900's.
Chuck