I'm having the same issue as this guy: http://www.tomshardware.com/answers/id-2900026/compatable-intel-dz87klt-75k-intel-4790k-devil-canyon... Compatable: Intel DZ87KLT-75K MB & Intel i7-4790k Devil's Canyon? [Solved] - Intel - Motherboards The board boots up fine and runs great, however when you try to reboot, either through the operating system or by hitting the reset button, it hangs with no video. The board has last July's BIOS update, and it ran fine with an i7-4770K, so what's the problem?
The i7-4790K is not a supported processor on the DZ87KLT-75K: Actually, none of the Haswell refresh processors are supported on this board.
http://processormatch.intel.com/Processors/CompatibleProcessors?componentName=dz87klt75k Compatible Processors
You may try other solutions found in the forum and on the net, but none are supported by Intel.
This link may help you. However, it is not supported by Intel:
Intel is no longer in the business of making desktop boards. Once the 8 series boards were released, support ended rather quickly.
The cost of doing a bios update is significant. That, and the exit from the desktop board market, well, the rest is history.
I do have a DZ87KLT-75K, with an i7-4771 processor. I have not tried Stephen's solution.
I apologize for any inconvenience.
I regret to inform that the Intel® Core™ i7-4790K Processor is not supported on your motherboard, any issue you might experience using this processor is expected. See here for the list of compatible processors http://processormatch.intel.com/Processors/CompatibleProcessors?componentName=dz87klt75k Compatible Processors.
The only issue that I've experienced is the reboot problem, other than that, the Intel® Core™ i7-4790K runs noticeably faster than the i7-4770K that I WAS running, so having to shut down & restart rather than reboot is only a minor annoyance at this point...