N4P is supposed to be -22% power @ iso-perf relative to base N5. Relative to N5P, however, TSMC’s numbers give something like +4% perf, iso-power, or -7% power, iso-perf. Honestly, kinda marginal gains.
Does beg the question, however. With Zen 5 widely expected to bring a much “bigger” core, but only small improvements on the process side (pre-N3), then what’re the implications for core counts and/or cost? Rumors seem to indicate that Turin is looking to be around 120 cores, give or take. If, for discussion purposes, we assume Zen 5 is scaled +50% from Zen 4, then that’s 120/96 * 1.50 / 1.06 (N4 density gains) => 1.77x the silicon area. Pretty big growth, and it’s hard to say what TSMC’s wafer prices will do between now and then. But I think that unless competition forces them to cut prices, the high end chips will continue to get significantly more expensive.
Also, even if AM5 gives them some room to grow, those scalers above give roughly +40% area per core. I’m not sure they have the room to absorb that and a third compute die, but maybe with an N3 refresh they could?