Synonym Performance

What performance problems are there between public synonyms verses private synonyms verses your own tables.

Another way to phrase it. If I connect as the table owner and do a query. Then connect as another user and run the same query public synonym, then by private synonym. With the last two queries be seen as already parsed SQL, and will the db_blocks in memory be used?

Also, where can I find information like this on oracle's web site?

Thanks.

• Paul