BOINC is not causing the heavy IO - it is the research application 'The Clean Energy Project' from World Community Grid.
That research application uses very heavy disk IO. This is why when a user signs up to participate at World Community Grid, 'The Clean Energy Project' it is not selected by default and there is a warning that says "Please review the system requirements before opting to participate in this project ". There is a link to the system requirements that states that 2GB of disk space is required. Additionally, if a user still proceeds to select the project, they will be limited to only have one workunit for the project at a time downloaded by the BOINC client. In the information above, the user has three workunits downloaded. This means that they took further action to change the default behavior through an option that is buried pretty deeply in preferences. Further discussion of this issue is most appropriately handled on the World Community Grid forums for this research application at http://www.worldcommunitygrid.org/forums/wcg/listthreads?forum=480 thanks, Kevin Reed World Community Grid Technical Support