I did a controlled experiment at 1.6vcore.

Removed lid from cpu, ran it at cool temps in prime 95 @ 4.2.

Shut system down. Let everything get to normal temps.

Posted next day at normal temps = dead chip almost instantly.

Take away the buffer ( IHS ) and the chip can die rather easy.

With the buffer there is potential to degrade the chip although I doubt it will spike it and kill it instantly I can assure you that damage can be done above 1.55v at the average users ambient temps.