I'm not sure i follow...If 125W is not the amount of watts drawn by the CPU at full load, then what is?
This is a very good question
The TDP is a random number plucked out of a hat the day before they print the box . However its safe to assume two things
1/ the package [ board , silicon wafer , head spreader glued on top] wont ever fall apart if you pump that number of watts in when you have a recommended heatsink on
2/ people arguing that their cpu is better because the TDP is 95 watt instead of 125 have no idea what they are talking about