After increasing the MemoryThreshold setting in the GeodatabaseManagerServices.config file, the services exceed their memory capacity without triggering the expected service restart. The MemoryThreshold setting remains below 2024 MB (the maximum memory usage of a Windows 32-bit application).
This is noted in bug MM54966. The MemoryThreshold setting is comparing against the active services' WorkingSet64 memory, rather than the more accurate VirtualMemorySize64. This causes GDBM to underestimate its memory usage, and can cause higher settings of this value to allow GDBM to exceed the 2 GB maximum of a 32-bit application in Windows.
Solution or Workaround
Until this bug is resolved, we recommend leaving the MemoryThreshold setting at the default of 300. This may cause more frequent GDBM restarts, but these should only take a few minutes (at most) per hour.