HP ProLiant DL385 G2 Server - Manual (Page 44)

Hardware options installation 44
13. Install the heatsink.
14. Close the heatsink retaining bracket.
15. Install the PPM:
a. Open the latches on the corresponding PPM slot.
IMPORTANT: Install the PPM only when installing a second processor.
NOTE: The PPM is keyed and the key must be aligned when installed.