The problem cube (when it ran, it runs at 30-32 Gh/s) behaved the same (would run for 5 minutes to almost two days) in all locations and with a 750watt and a 650watt power supply.  It behaved the same if switched the pools, if I changed the IP, if I changed the clock, etc.


The cube without the drop-out problem is the one that hashes slowly all processors are showing okay (no Xs) but only the first three boards are showing any hashing.   I'll take it apart and reseat the boards and check the heatsink screws.

thanks