In addition to what others have said, some additional (external) factors may also contribute to the results you see, for example:
  1. Disk I/O: different filesystems read in different ways and scheduled I/O can be affected by that as well as block size (see tuning information for "elevator" algorithm on ext3).
  2. CPU allocation: other processes can be competing for the same CPU.
  3. Available RAM: loading an entire file into RAM is much quicker than loading a segment of it into virtual memory or a paging file.

In reply to Re: Why is "for" much slower than "while"? by steve
in thread Why is "for" much slower than "while"? by di

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