What parameters should be modified after upgrading RAM memory in Oracle server
In 9i, multiple parameters are used for sizing components of the SGA. Below is a typical (but not complete) list:
DB_CACHE_SIZE
JAVA_POOL_SIZE
LARGE_POOL_SIZE
SHARED_POOL_SIZE
And SGA_MAX_SIZE, if set.
Also I assume for simplicity that you use automatic PGA management, so for PGA:
PGA_AGGREGATE_TARGET