-----Original Message----- From: boost-users-bounces@lists.boost.org [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Aljaz Sent: Thursday, March 08, 2007 7:31 AM To: boost-users@lists.boost.org Subject: [Boost-users] iostream large file - performance I've been testing fstream libary to read a huge text file (45 megabytes), which has around 2 million lines.. When I do (using fstream): It takes about 9 seconds to read the whole file.. If I open file it with any 'good' text editor (editplus, notepad++ for instance) it takes a few seconds to read/load the whole file.. [Nat] A good text editor might *not* read the entire file. It probably reads enough to display the first page, plus another couple of bufferloads to anticipate you scrolling forward. From then on, it probably reads more on demand.