Ask HN: PC working/processing so much harder on low data connection, know solve?

Why PC's mainly laptop's, wifi is working and processing so much harder and much more heavily when the internet data it receives is at low speed (40 kbps max) and/or intermittent, as opposed and not due, to weak wifi signal strength i.e. its low dB. This's outright conspicuous when performing a media streaming

What actually is which processor(s) is/are working and/or searching on, and what actually has triggered it/them to obligatorily working and processing in such very hard which leads to real problem: quickly gets overheating?

How do we mitigate or solve this (mainly my) problem ?