I have been running into problems like this with my Emby plugin. I have 4 cores and 16 gig of ram. I have emby using 3 of the 4 cores. When transcoding a tv show from a remote location during parts of the process i get to 75% cpu, which is expected. If I try a movie, most of the time my cpu jumps to 100% and if I don't kill it in time, it will crash my entire server. My Ram never gets close to 100%. This only started happening after we were warned about the cpuset code change. I have tripled check to make sure I changed it and it looks right ( I can't check right now) and like I said, it normally just uses up to 3 cores. I haven't gotten the chance to test it since upgrading to rc1.