If you purchased an Official AMD Retail Box processor you have three year AMD Warranty on it: https://www.amd.com/en/support/kb/warranty-information/rma-03
The AMD Warranty becomes effective after your Retailer/Vendor Warranty or Return date expires.
Just fill out a AMD Warranty from here: https://www.amd.com/en/support/kb/warranty-information/rma-form
You will need your Official Retailer/Vendor's receipt showing you as the original owner and date of purchase plus whatever other documents or photos AMD requires for the Warranty.
