A single-layer board on chip package substrate and a manufacturing method thereof are disclosed. In order to select one of the multiple cores 21, 22, 23 in such a processor, an execution time of tasks which are performed multiple times is determined Based on the determined execution time on the individual cores 21, 22, 23, an appropriate core 21, 22, 23 for further executions of a task is selected. The invention includes a user device for communicating with at least a public network andor a private network.