Welcome to the forums.
EVGA FAQs:
Post Code C indicates an issue with the CPU. This can be caused by a defective CPU, out of spec Power Supply, Bent CPU socket pins, CPU incompatible with BIOS version or defective Motherboard. (That mobo has
support those CPUs you tried right from the get-go, BIOS Version 1.00)
Motherboard Manual Page 16: 8-pin EPS Connector
The EPS is dedicated power for the CPU (See Page 38 for more specifics to the connector itself, and associated wiring/pinouts). Carefully choose the correct power cable by consulting with the installation manual for your power supply. This connector is designed to only work with an EPS or CPU cable. System builders sometimes make the mistake of plugging in a PCIe 8-pin or 6+2-pin connector, which will prevent the board from completing POST and possibly short or damage the board. Although PCIe and EPS cables appear similar, they are wired differently and attaching the wrong connector may cause damage to the motherboard. Alternatively, if no power cable is connected or detected, the system will not POST and will hang at POST code “C.”
Motherboard Manual Page 38: The 8-pin ATX 12V power connection(s), is used to provide power to the CPU. Align the pins to the connector and press firmly until seated. The secondary EPS, if present, is optional for improved overclocking. Please remember to make sure that the tab on the EPS socket is aligned with the release clip on the cable. NOTE: If the tab and release clip are on opposite sides, yet the power connector fits, then you are using a PCIe 8-pin cable, which WILL damage the board if powered on. Please review installation instructions from your power supply manufacturer to verify which connectors may be used for the CPU power.
The 8-pin CPU power connector is the only one you need connected at this time..The 4-pin connector is not essential to running the system, it provides additional power to the CPU better stability under a heavy load, overclocking, and/or benchmarking..Disconnect the 4-pin connector for now and reseat the 8-pin connector on the mobo and PSU-end..Turn off Eco Mode for now too on the PSU.
Just for kicks, you could try the other BIOS..Slide the switch located above the Intel SATA ports and then restart your PC.
If all else fails,
Contact EVGA Customer Service about an
RMA..If you need to RMA, be sure to read the
Shipping Guidelines about how, what/what not to send back.
Also be sure to read the
Ultimate Self-Starter Thread For New Members if you haven't yet..Lots of good info there for you.
Good luck with it!