Well I compile libguestfs (http://libguestfs.org/) on POWER8 fairly regularly and the compilations just fly past. I haven't benchmarked it, and I'm not allowed to benchmark it because of the NDAs we sign, but it's obviously faster than the Intel machines we have. Because of the single-threaded parts of the build (eg. ./configure), these builds benefit much more than just having lots of cores - Amdahl's law and all that.
