I am doing an upgrade, and the person will has a celeron 420 in the system, which is a better upgrade the 2140 or the 925? the system will not be overclocked, and those are the two processor to choose from, not any other C2D or Pentium D processor, just those two. (I have both, and will be selling the guy one of those two pretty cheap, so thats why those are the two choices, just want to make sure i tell him which would be the better performer). Heat/wattage is not an issue, so power saving doesnt come into play, just which is better performing?