Most strange. Could you give us the listing frop top or the like? The normal case, as you are probably aware, is that the children get fat (use a lot of memory) and your system goes into thraashing.
This sounds like you have some other problem. Are you using awl (it is on by default in 3.x) or bayes? Possibly they are all trying to do expire runs on a huge database that has somehow managed to grow out of control. The other parameter you might want to set, if you haven't, and if the kids are getting fat, is --max-con-per-child. It defaults to something quite large, and setting it down to 20 or so has helped many people. Loren