the database becomes quite slow during peak hours.
as i see
it's taking quite long for queries on views compared to tables including dd views like v$sqlarea.

in v$filestat iam finding good many reads and writes against
temp tabelspace datafile.

v$waitstat and v$rollstat report no contention.

my phy ram is 512 sga is 336 and shared_pool_size is 120
hit ratio for librarycache and rowcache is above 90