Random freezes sounds much more like either the CPU overheating or the memory settings being incorrect.

There has never to my knowledge been any problems specific to motherboard revisions.

Try resetting your memory speed to 70ns through the BPPC boot menu (hold the escape key pressed while rebooting). Check that the PPC chip is not overheating. If it is too hot to touch, it's time to check if the fan is running as it should and try to cool it better.