I am not a tech person, but I cleaned out my secondhand PC today, and it took hours with the sheer amount of dust accumulation. The fans were nearly overloaded with it!!
Does a clean PC run better / faster than one filled with dust? Or is it more a matter of keeping the fans running easily? Or something else…? Idk, maybe I imagined it, but it seemed to boot much faster after cleaning. Could be wishful thinking!
Never underestimate the effect dust can have on airflow and cooling in general
In the old days when cases were much less designed for good air flow, in the summers I used to take the side panel right off my rig.