Upon bootup of the actual game, not the launcher, the CPU usage on my PC shoots from an average of 20% idle usage immediately to 100% usage, bogging any other programs down in the process.  This is not an issue of Minecraft directly affecting applications, rather an issue of unusually high usage of the CPU.  Prior versions of Minecraft do this as well, but to a much less noticeable effect.  (Tested back to 1.7.10).  

Is this intended behavior?  If so, what are some recommendations I can use to reduce the load on my pc when Minecraft boots up.  If not, what can I provide to assist in determining what the root cause of the issue is?