LINQ是如此之慢，拥有庞大的数据库表

I have an ASP.Net MVC software with SQL server backend. I have a table with 80 column, currently counting about 975413 records. I am using Linq for the transactions with database. The problem is that I noticed that it is taking so long time to execute commands like SaveChanges(), Find(), Select().. and so. I have an ASP.Net MVC software with SQL server