IBM pSeries 690 Service Manual page 84

v Memory is available in 4 GB, 8 GB, 16 GB, 32 GB, and 64 GB inward-facing and outward-facing
increments.
v The following memory configuration considerations are recommended to ensure the optimum
performance is obtained for the system:
– Memory should be installed in identical pairs.
– All available memory locations should be populated with memory cards.
– Memory sizes should be balanced as closely as possible across all populated MCM locations.
v The number of active memory positions on a system is related to the number of populated MCM
locations. Two memory positions are activated for each MCM installed.
– The first MCM installed activates the first and second inward-facing memory positions.
– The second MCM installed activates the third and fourth inward-facing memory positions.
– The third MCM installed activates the first and second outward-facing memory positions.
– The fourth MCM installed activates the third and fourth outward-facing memory positions.
v It is recommended that all systems have access to a 4-mm or 8-mm tape drive for submission of
system dump information, if required. This function can be accomplished through locally attached or
network-attached devices as appropriate.
64 Eserver pSeries 690 Service Guide