[Macha]

A modern 1.6ghz laptop cpu like the 1240U is probably fine for factorio.

A Core 2 Duo E8400 at 3ghz probably isn't.

They don't want to test and then list the minimum CPU for every generation of cpu for the last decade or more when listing system requirements. So they go a little higher in the stated requirements than is probably needed with newer gens so people don't get angry and disappointed that their older gen cpu doesn't run well despite having the listed clock speed.