i dont consider 1.55v on thuban 24/7 for most people. most dont push it past 1.5v because air cooling just cannot keep it stable around there (unless you have a fan that makes you deaf)

also the crashing in idle ive seen before, and its because my idle voltage was too low. i would turn that up a few notches or just turn off CnQ and see if that fixes it.

can you test power consumption with the 2 different chips? it would be great to see identical load wattage and see how different the temps are, since that can give a very clear indication if the cpus are set with different calibrated sensors.