Unable to clock to 1.4 mhz with ak73proa

I’ve just assembled an ak73 pro (a) running a 1.4 mhz amd cpu. When I booted up, the speed was showing 1052 mhz x 10.5. This ran ok. I changed the jumper fsb from 100 to 133 and the pc then boots up showing 1.4 mhz but then freezes shortly after boot up has finished. I changed the dip switch from default to 10.5 X 133, but this didn’t help.