CPU, memory and deadlocks will not always indicate performance problems. 'Spotlight on SQL' or 'Spotlight on Windows' might spot many other issues that are not apparent in PerfMon such as excessive disk I/O or too many open SQL connections.
There is no harm in trying those products so why not try them?
Sharepoint actually stores indexed content in two places, the SQL database and the index folder. When Sharepoint search Sharepoint sites it stores the index results in the database, when it searches non-Sharepoint sites it stores the index results in the index folder. It's strange but true. I got it first hand from Microsoft.