Considering purely speed with most kinds of mathmatical algorithms leads you to think C is better to Perl. However, modern computing power almost makes this problem a non-issue for anything but 3D games or high end simulators.

Well, realtime 3D is my field of choice, which gives me some appreciation for C. :-)

It's rather naive to say that, in general, program speed doesn't matter because (a) modern computers are just so damn fast that they chew through any problem in no time or (b) any program can be made fast enough by throwing hardware at it, because modern hardware is so cheap for what you get. Even in good ol' web automation, which many people think of as the only thing that Perl's good for (lo these many years ago, I was victim to this fallacy), speed is important, especially on large data sets.

But especially on large data sets, it isn't language speed that's important, it's algorithm speed, first of all asymptotic order, that's vitally important. It doesn't matter whether your language of choice runs a thousand times faster than mine, statement for statement; if your program is O(n^2) and mine is O(n), on even remotely large data sets I'm going to win. That's the point. Forget about language-speed pissing contests. Pick up an algorithms book and start learning.