[azurelogic]

All computers have the potential for slowdown as they age because 2 things naturally happen: cooling systems clog with dust and thermal paste degrades. Both of these eventually reduce the efficiency of the cooling system, resulting in higher CPU temps. Unchecked, this can result in CPU throttling by the hardware itself.

[pixl97]

3 things. Hard drive/SSD. Full ssds rUn slower naturally. Hard drives with bad and remapped sectors can go dramatically slower.

[Pulcinella]

I would assume that if you had no fan, then the only things that could “degrade” on a computer would be the battery, thermal paste, and the capacitors (and maybe the screen backlight in a laptop.)