ELI5: What's the difference between someone who has a learning disability and someone who's just stupid/slow/dumb?

I would think of it in terms of a computer.

Stupid or dumb would just be someone with a slow processor. Everything works fine, it just doesn’t work that fast.

A learning disability would be a hardware defect. Maybe there is a problem in ram causing a corruption of data… the computer is working perfectly fast enough, it just encounters errors which make it difficult to complete a certain task.

Explain Like I`m Five: good questions, best answers.