To increase optimization and performance, the Oracle Database Client and server process memory requirements are greater than in previous releases.
Every release of Oracle Database includes new features and capabilities. To provide optimal performance for the increased capability of the database, there can be an increase in the Oracle Database Client and Oracle Database Server can increase from one release to the next. The memory requirement increase can vary from platform to platform.
As part of your upgrade plan, check to determine the memory requirements increase that can be present in a new Oracle Database release. For example, in comparison to Oracle Database 11g Release 2 (11.2), Oracle Database 12c on some platforms can have as much as a 5 MB memory increase for each client, and a 10 MB increase for each server.