Chad Callihan provides some helpful tips around read-ahead:
What are read-ahead reads and how do they impact SQL Server performance? Read-ahead reads allow SQL Server to think ahead to pull pages into the buffer cache before they are actually requested for a query. Up to 64 contiguous pages from a file can be read and the ability to read-ahead can be used for both data pages and index pages. Once data is in the buffer cache, it will not need to be pulled in for future queries unless it has been pushed out by other SQL Server tasks.
Click through to see what they are and how you could disable them if you really need to.