We've discussed this issue just a few pages ago in this thread, although in the end it wasn't clear even if the problem existed at all. Can you "prove" that your CPU is actually going down to 125Mhz, or is that merely the output of "kernel-config show". If the frequency is being avoided, it doesn't matter if the minimum is set to that frequency. Check with e.g. conky and see how low the CPU goes with nothing else running (or use powertop if you know how to). AFAIK most people avoid 125Mhz but allow 250Mhz, which doesn't seem to harm. Why do you need to avoid both 125 and 250?