Toad starts up is fine but when initiating a connection to the 11g database it takes a long time (3+mins). This is not a problem for all databases.
There is no way around that noted script in the connection process, but the following are suggestions to address the performance issue.
(Only for Toad 10.6 and newer)
1. In Toad, go to Options | Oracle | Optimizer Hints.
2. Add a RULE hint for DBA_SYNONYMS on Oracle 11G.
Verify statistics on the SYS tables are current (especially the tables that ALL_SYNONYMS uses).
Running the query through the Oracle Tuning Advisor and see if it can generate a profile for you.