[kllrnohj]

Marketing. It's the same reason AMD decided to tier the Ryzen lineup into a 3, 5, 7, and 9.

Intel had products with TDP of 65w and 125w, so AMD "matched" that by making up a TDP formula to get the results they wanted. At the time, Intel's TDP was actually mostly accurate. It would turbo above that, but only for a few seconds before dropping to the TDP limit.

Then when AMD started winning, Intel had to get match them in return. If AMD's "125w TDP" parts could turbo forever, then why shouldn't Intel's? And so that's what they did. And just like that over a few generations TDP became entirely stupid & without a shred of meaning.