One of my computers is running a Coppermine P3 500 @667 on the BX6-2 whith a slocket.
My videocard (CL Geforce 256) couldn´t handle the speed until I put an Extra fan on the backside of the card to give it some extra cooling.
No there is no problem what so ever running at 133.
Btw ,why did you get an EB?, you would have been better off with an E since everything over 100 mhz FSB would have been "foor free".