Don’t know if this is common knowledge, but here’s how to enable all your processor cores for compilation in codeblocks…
Go to Settings -> Compiler and Debugger… search for the Other settings tab: number of processes for parallel builds
(found it here: http://forums.codeblocks.org/index.php?topic=7964.0;prev-next=next)
that’s a great tip… I will add it to the setup guide to cb, which needs some updating and love.
Wow that is such a good trick. I always dreaded accidentally hitting the “Rebuild All” button but now it’s so quick it doesn’t even matter !
Awesome tip, this significantly improved my build speed! 
In the current version of CB (13.12) this setting can be found in: Settings > Compiler… > Build Options
For me the optimal value for “Number of processes for parallel builds” is equal to the number of (logical) processors in the computer. You can find this number by typing the following in a shell / command prompt:
echo %number_of_processors%