Wow, your computer configuration is excellent and matched among components. So wonderful! I've found similar situation, the simplest workaround is to re-install Windows with all cores enabled. But re-installing O/S is not always the good and safe thing! And even if reinstall it, the problem might also be unsolved. So I suggest you boot up your system with another O/S, such as Ubuntu 16.04.1 x64, you can download from Ubuntu official website, and make a live USB. Boot up your computer with that live USB stick, and find whether it would work well when all cores been enabled. If so, you are welcome to contact with Microsoft support for further solution. If not, you might possibly contact with Intel support for processor replacement. Anyway, I just wish you good luck!
I am sorry to hear you are having issues with your Intel® Core™ i5-6600K Processor.
I have some troubleshooting you could follow.
1. Boot the system with a simple configuration, 1 stick of RAM, no GPU.
2. Test each stick of RAM on each DIMM slot (one at a time)
3. Enable cores one by one
4. You can certainly follow Janagewen's recommendation of installing Windows again.
This are steps to be done with all cores enabled, but step 3.
Please let me know how it goes.
I've tried your troubleshooting steps with no luck. I also can't install Windows with all cores enabled. it will not even boot into the Windows installer with all cores enabled. I've tried to send a warranty request to intel but for some reason when submitting the request I get an error asking me to try again later.
I understand, thank you for the answer provided!
In this case, another option is via chat or phone support.
Here you can start a chat: http://www.intel.com/content/www/us/en/support/contact-support.html?iid=intelfb
Select processors then chat.
or over the phone:
North America: Phone Number: 1-916-377-7000
Monday - Friday
7:00 AM to 5:00 PM (Pacific Time)
Hope you can reach us there