Going from a single CPU to a dual CPU would, in theory, double performance _at best_. In other words, only under workloads that supported multithreading perfectly.
But in the real world, the perceived performance improvement was more than doubling. The responsiveness of your machine might seem 10 or 100x improved, because suddenly that blocking process is no longer blocking the new process you're trying to launch, or your user interface, or whatever.
Very interesting observation. Multicore systems have been fairly standard for the last 10+ years, and while you occasionally notice a misbehaving process hog an entire core, it never visibly impacts system performance because there are still several other idle cores, so you don't notice said "hogs."
It's much rarer to see misbehaving multithreaded processes hog all of the cores. Perhaps most processes are not robustly multithreaded, even in 2025. Or perhaps multithreading is a sufficiently complex engineering barrier that highly parallelized processes rarely misbehave, since they are developed to a higher standard.
> Multicore systems have been fairly standard for the last 10+ years, and while you occasionally notice a misbehaving process hog an entire core, it never visibly impacts system performance because there are still several other idle cores, so you don't notice said "hogs."
Except on Windows laptops. Where, although the computer is idle, your favourite svchost.exe will heat your system and trigger thermal trottling.
100%. Its common for non-technical users to complain their laptop is faulty, because it gets hot and the battery drains very quickly. They have no concept of a runaway process in a hard loop causing this.
But in the real world, the perceived performance improvement was more than doubling. The responsiveness of your machine might seem 10 or 100x improved, because suddenly that blocking process is no longer blocking the new process you're trying to launch, or your user interface, or whatever.