IO from a mapped file vs IO using filestreams

Question

I am working on an application which needs to deal with large amounts of data(in GBs). I don't need all the data at once at any moment of time. It is ok to section the data and work only on(and thus bring it into memory) a section at any given instance.

I have read that most applications which need to manipulate large amounts of data, usually do so by making use of memory mapped files. Reading further about memory mapped files, I found that reading/writing data from/into memory mapped files is faster than normal file IO because we end up using highly optimized page file algorithms for performing the read write.

Here are the queries that I have:

1. How different is using memory mapped files(I am planning to use boost::file_mapping and I am working on windows) for file IO than using file streams?
2. How much faster can I expect the data read/writes to be in case of memory mapped files when compared to using file streams(on a traditional hard disk 7200 rpm)?
3. Is memory mapped files the only way to deal with such huge amounts of data? Are there better ways of doing this(considering my use case)?