I think the laptop hardware pre Apple M chips was just terrible and has pretty much stayed that way. There’s a reason why Apple moved away from Intel.

Before M chips an Apple Intel laptop was just a shiny wrapper for a PC laptop experience: fans turn on to full blast all the time, battery lasts <3 hours under any regular usage beyond just browsing (say having an IDE open, and frequently switching between apps). Laptop would get hot to the point where you need padding if you keep it on a lap so you’re not boiling yourself. Made for a good leg warmer during the winter though haha.

With an Apple M4 laptop, the only time I’ve heard the fan turn on is when I almost 100% filled the memory with some local LLM model. I can’t recall any other times. Battery life is finally as advertised, can last many hours, laptop is consistently fast, never gets hot and any CPU throttling is not perceptible under medium to high CPU usage.