Larry,
Your processor is reaching Throttle temperature, which is 100C for your i7 4790K. It's highly likely that one of the stock cooler's push pins has popped loose from the motherboard, which also explains your high idle temperatures.
To troubleshoot this problem, run your rig so that you reproduce the high temperature conditions. While keeping an eye on the temperatures, press down firmly for about 20 seconds on each corner of Intel's stock cooler. When you see a significant temperature drop, you've found the loose push pin.
Please read this Tom's Sticky:
Intel Stock Cooler Installation Guide -
http://www.tomshardware.com/forum/338655-28-intel-stock-cooler-installation-guide
This Guide will explain in detail how to get your cooler securely attached, which will fix your problem.
If you don't plan to overclock, then Intel's stock cooler is barely adequate.
Here's another helpful link:
Thermal Paste Comparison, Part One: Applying Grease And More -
http://www.tomshardware.com/reviews/thermal-paste-heat-sink-heat-spreader,3600.html
Also, what is your ambient temperature?
CT