Just some hints about Performance and Virus Scanner.
Whenever there is an issue about performance - I know it is always - we check the Virusscanner Software.
Opening an assembly with Virus Scanner turned on 3 Minutes - turned off less then 40 seconds
Here are some hints about it:
Important: Check that the Virusscanner has really recognized the new rules
Hope this will help to solve some of the performance issues
Have a nice weekend