Interesting, my Xeon 5420s refuse to finish a wu. According to BoincTasks they are using no cpu. The have been running for over 16 hours. I've taken those 16 cores off of Docking and put them back on NRG.
@DrPop - your sister systems don't appear to have finished anything either. You may want to check them.
Edit: I'm trying it again. I detached and reattached. They seem to be running okay at this point, but BT is still showing no cpu usage. Task Manager does show them maxed out at 100%.