My recommendation still is to contact Intel Customer Support for warranty replacement of your i7-5820k. You can use the following options to do that:
Online warranty: Service Request Email
Chat support: Contact Support
At this point you have done the recommended troubleshooting steps and it seems that the issue persists, what I would recommend is running the Intel® Processor Diagnostic Tool Intel® Download Center, if the CPU overheats we will be able to confirm it with this tool.
Could sent us the report from the Intel® Processor Diagnostic Tool.
Please once the the diagnostic is done go to File>View Results File and sent the txt file.