Tips for Fastest Code challenges What general tips do you have for how to answer fastest-code challenges?

Please post one tip per answer.

The objective of these challenges is to make the program that will run in the least amount of wall-clock time given a specific set of computer specifications (based on who will be judging the timings).

Please keep tips specific to fastest-code and not fastest-algorithm; you can assume that the coder has already found the most efficient algorithm to use.
Language

For example, Python is an interpreted language, not a compiled language, so it would surely be faster if you wrote it in C to begin with.

Rust, C++, C, javascript, and Haskell seem to be popular choices. One would have to evaluate them.