What is also important is that the database home page shows the latest ADDM findings. This is a proactive diagnostics engine that runs every hour by default on the database, and generates a list of recommendations.
Clicking on the ADDM Findings button takes you to the last ADDM Performance Analysis page, which is displayed in the following screenshot:
Informational findings are also shown. ADDM lets you know if the database is CPU-bound or I/O-bound, it lets you know of hard/soft parse issues, top SQL statements impacting the database, any locking issues, and so on.
ADDM is also RAC aware and informs you if there are any networking/interconnect ...