How to improve entity framework performance with large of database?

Improving the performance of EF for big databases starts with designing and normalizing your DB as good as it could be. Then, you have to manage EF configuration based on your requirements, specially the configuration related to Lazy Loading and Proxy Creation. Kindly refer to this useful post on Stack Overflow: Is EF really production ready for large application?

there are several steps you can improve the performance 

1)avoid to put all DB object in one single entity model  

2)Disable change tracking for entity if not needed

3)Use Pre-Generating Views to reduce response time for first request

4) Avoid fetching all the fields if not required

5)Use Compiled Query wherever needed

6...