"rubbish", oh, not necessarily. Onboard sound may be fine. Go by your actual experience and wants. If you're listen to music a lot and really aren't satisfied with your sound, that would be a valid reason for installing an add-on sound card. Or, perhaps you play certain games where sound is a major element and you want better sound. But, for the things many computers do with their computers on a daily basis, onboard sound may be fine.