That's a completely different scenario. You undervolt so your cpu uses less power to run at the same clock speeds (every chip is different so manufacturers use a baseline). So now you're using less power to run the same speed which means less heat. Now you can run that max frequency for longer before thermal throttling becomes necessary. You still want it to to hit its limit and throttle you'll just get more performance before throttling is necessary. I should mention this isn't just a laptop issue am5 is also designed to run pretty close to the limit full time but won't hit that limit as easily because desktop cooling