This is Ubuntu 14.04.4 LTS / x86_64 / g++ 4.8.4 / Python 2.7.6 and ROOT 6.08/00 here.
When in ipython 5.1.0 I try to import anything from ROOT (e.g. “from ROOT import TRandom”), the CPU usage immediately becomes 100% and stays like this.
There is no such problem with the current ROOT v5-34-00-patches.