> why people continue to misunderstand this befuddles me. You might want to check whether your befuddlement is due to your own misunderstanding of the topic.

> why people continue to misunderstand this befuddles me. You might want to check whether your befuddlement is due to your own misunderstanding of the topic. How many switching regulators have you built? We aren't living in fixed AC transformer days anymore, even the shittiest PSU won't behave like you're making it out. The legally required PFC will already prevent it just by itself, before the main 400V DC/DC step-down even gets its hands on the power. And why are you even mentioning 3V/5V? Those rails only exist for compatibility, modern systems run almost entirely off the 12V rails; even SATA power connectors got their 3.3V (it's not 3V btw) pins spec'd away to reserved by now.