Slow return to wcf

Question

Hello.

I have a Silverlight application that performs queries to the database SQL Server. In a table I have 1 million entries, as follows:

starts with the letter A: 130.000

starts with the letter B:  16.000

starts with the letter C:  70.000

When I run the query the first time, in case the letter A, the return is faster, the later will become increasingly slow. The impression I have is that the buffer will accumulate data.

Does anyone have an idea how to solve this?

To work with large amounts of data and simultaneous queries, how do I configure the properties of the protocol NetTcpBinding in web.config?

Thankyou.

Teles