Hello Wilgard,
There is no way to decrease your devices. A device is really an installation, rather than a computer. Every time you install the software, a unique ID is created for that client, which the server always remembers, ready to accept a message from that ID (device). Later this year, we intend to revamp that section of the code, but we shall just have to wait to see what replaces it.

I have been following some posts on other BOINC projects where they did allow the database to merge devices. This sort of massive reorganization of the database slowed their servers to a crawl, so they had to disable the feature. Then they discovered that errors were introduced into their databases during the reorganization. I have been thinking about database design issues and this problem. My own preferred solution is the introduction of a whole new level that leaves the low level devices alone but lets the user map them to computers (or some similar entity name). Complicated, but it avoids many tricky points. But it would be programming intensive to give the user access to edit the computer list to the user's satisfaction.

Lawrence