Question about ASUS ROG Crosshair X670E Hero

If you buy it today, very unlikely you need to update it, because X3D support was introduced in April this year (at latest). So most probably your MB will come with a newer UEFI/BIOS. However updating the BIOS certainly recommended. On the other hand, if you buy it with an older BIOS together with the newer X3D CPU, you will be in trouble because you will not be able to start your system up, therefore BIOS update will be impossible (as it requires a working CPU).