xcode5 cpu %100

1. Change Always Search User Path to NO in Project build settings (bolded).
2. Remove -objC flag Other Linker Flags (also bolded setting).

And then delete Derived Data and wait until Xcode reindexes.

I am not sure which of them helped bacause I changed both of them at the same time and I am so behind my schedule I have no time to test it. I will improve this answer when I reproduce the bug and solution in spare time.

However, there is a hint: *Rethink and recheck your project / targets build settings.*

It is highly probable that this strange behavior may be caused by some unfortunate combination of build settings.

谷歌  

http://stackoverflow.com/questions/10522936/xcode-4-3-2-and-100-cpu-constantly-in-the-idle-time