Well the VRM's can be underpowered, sure. But a no-boot? That seems highly unlikely that they'd heat up so fast.
Maybe if you can get into the BIOS, quickly turn off all the performance enhancing features like PBO and other MCE-like features.
That having been said, the 1800X isn't that much less power hungry. So if that runs flawlessly, i'd look somewhere else than VRM.
Maybe return it, and get a replacement.