Most likely just need a BIOS update, the old cpu voltages and frequency list is wrong. Some times you can get away with it if you install the latest intel CPU chipset drivers. It will update a file that windows loads to override the CPU microcode.
Get it directly from intel: https://downloadcenter.intel.com/download/20775/Intel-Chipset-Device-Software-INF-Update-Utility-
I would not expect it to be your power supply.
NotTrash :
Yeah its a i7 4790k updating the BIOS would probably help then. The motherboard is older than the processor for sure and I did think some voltages looked a little funny. Could the power supply be an issue? Its a 600W Corsair CX.