In this example, the information is useful only if the user already has high-speed USB ports installed.
Otherwise, the user isn't likely to do anything different as the result of it.
Show when: When the triggering event occurs.
Show how: Use the real-time option so that these notifications aren't queued when users are running a full-screen application or aren't actively using their computer.
Show how often: Once.
Annoyance factor: Medium to high, depending upon users' perception of usefulness and relevance. Not recommended if there is a low probability of user interest.
Alternatives: Don't notify users.