said by Guspaz:Dunno, a first-gen P3-866 has a TDP of 31W all by itself, let alone the rest of the parts in the system. Not nearly as bad as a later P4 or Pentium D, of course.
TDP isn't the amount of wattage required to run the cpu. It's the amount of heat generated that needs to be dissipated by the cpu cooler in order to not fry it. The TDP of a P3-866 is 22-36w, the MDP(Maximum design power) is 27-33w. MDP is what you're looking for, and the MDP is the "worst case" in terms of wattage draw.