TROGDOR

A few minor notes:

• As moritz indicated, you haven't proven that the I/O is the problem. You're doing some operations other than reading, any of which may be the problem. Be sure to profile before assigning blame.
• BrowserUk and moritz have also shown you a couple tips to improve the reading speed.
• Perl isn't a "speed is king" language, so having something 1/5 as fast as C isn't altogether unusual. Normally I/O dominates many operations, so perl code is often quite close to C code in wall-clock performance.
• Keep in mind that while perl is slower than C/C++ at some things, it makes other tasks quite simple to do. So often it makes more sense to compare an entire program, rather than one phase of it (I/O).

Just as a reference, I do (in my day job) quite a lot of file processing in both C/C++ and perl. I often find that the perl stuff runs slower, but not enough so that I want to write all my processing programs in C/C++. I find it so much simpler to do regex and complex data munging in perl, that when I have to whack a file using a good bit of intelligence, I tend to use perl first. If I need to whack a large file with just a little simple code and speed is of the essence, I tend to use C/C++. Only rarely do I find that I have to optimize a perl program or rewrite the program to use C/C++.

As usual, YMMV.

...roboticus