Comment 12 for bug 73744

Well, top only reports cpu usage in the exact moment of measurement or at least something very similar to this... i.e. you could even get 100% cpu usage by a app that is sleeping most of the time.

A better way would be something like gkrellm's cpu usage graph or just the cpu time of the progress compared to the real running time.

So could you please start rhythmbox, play music for a defined amount of time and report what the time column of top says (and how long you played music).