Ibe, who joined from Liverpool for £15m, struck after 12 minutes with a driving run and a curling finish.
Cardiff kept possession well but created few chances, with Joe Ralls' low wide shot their best effort.
The Bluebirds' opening league game is at Birmingham on Saturday, 6 August.
A fine individual goal by Bournemouth's club record signing Jordon Ibe saw them beat Cardiff City in the Bluebirds' final pre-season friendly ahead of the new Championship campaign.