Could be a bad cpu mount. The newer 10th gen cpu's have more pins on the motherboard increasing the likelihood for a bad mount. Make sure it goes in flat and you've applied even mounting pressure. If it's not that check the pins on the motherboard and the pads on the cpu to check for any contamination or bent pins. If neither of them check all the 24pin and 8pin are both plugged in properly. If not that just go back over everything. It could even be something like RAM, make sure they are in slots 2 and 4 and they are mounted right. Other than that I'm out of ideas right now, contact intel and gigabyte, they're definitely smarter than any of us, they designed the bloody stuff.