Comment by supriyo-biswas
2 years ago
Additionally, it may also be that accesses to a single file allows the OS to efficiently retrieve (and IIRC in the case of Windows, predict) the working set allowing the reduction of access times; which is not the case if you open multiple files.
Not so much working set, as you only have to check the access control once. Windows does a lot of stuff when you open a file, and creating a process is even worse.