"overvolted, overclocked and inadequately cooled" - sounds like a default GPU setup (only half-joking). IIRC the optimal performance per watt for a modern consumer GPU is at half the stock TDP, according to MonsterLabo.
People have experimented with GPU's that have been used for crypto mining (kind of a worst case scenario) and haven't managed to hit any reliability concerns so far - the cards seem to work just fine.
They also undervolt their cards, because it's more efficient.