Just as an update, although the board I got in the end tested allright (memory and CPU would run at specified speed) I have only now tried to put this thing into a permanently running machine and failed.

There is some kind of noise coming from the battery area. It is there even when the board is powered off and just has the battery. Removing the battery silences it. It is kind of a "static chatter", like little discharges about 10 times a second. It's bad enough that I can't use it for the fileserver I planned it for, much louder than even the Zalman 7700Cu I put on there.

Any idea what this could be?