Compaq ProLiant 850R Setup And Installation Manual page 76

The server is shipped with a DIMM in DIMM socket 1 (System Board
connector J6).
The recommended order of DIMM installation follows:
Install the second DIMM in DIMM socket 2 (System Board connector
J7).
Install a third DIMM in DIMM socket 3 (System Board connector J14).
Then install a fourth DIMM in DIMM socket 4 (System Board
connector J9).
Any combination of DIMMs may be used in the ProLiant 850R server as long
as at least 32 MB of memory is installed; for example, one 32-MB module, one
16-MB module, one 64-MB module, and one 128-MB module may be used
simultaneously.
CAUTION: Use only Compaq DIMMs. DIMMs from some other sources
are known to adversely affect data integrity.
Figure 3-25. DIMM slots identified on System Board
J6 J7 J14 J9
3-25