EMC 2MB memory boards on 780 crashes 4.2

[Tom Dunigan]

Help, Just added 4 Mbytes of EMC memory (2 Meg per board)
to existing 4 Meg of DEC E type memory.  DEC diagnostics
show all well; configuration at boot shows 8meg, but
shortly after (not immediately) programs start running
in the upper 4 Meg (EMC memory) the system crashes either
with no panic or various flavors of panics, plus strange
happenings on user terminals.  Removing the DEC memory
and running only with EMC memory, UNIX gets through configure
but never comes out of fsck on root  (disk is flashing) . . .
HOWEVER, booting up VMS with only EMC memory works fine.

What magic do I need? It is as if the interleaving or
or page mapping is faltering . . ..  

thanks
  dunigan at ornl-msr