Why don't you try to set it up so that it stays at a constant 4.5Ghz? I bet that'll fix the problem although you won't be able to take advantage of the energy savings. Personally I much rather my chip staying at 4.7Ghz rather than constantly jumping up and down. Too me that would put too much stress on the CPU. Just my opinion.
But any idea as to why the overclock settings seemingly just ceased to be recognized?