I wonder what exactly causes "instability" when overclocking/undervolting in a processor. Transistors don't have enough time to switch, but it matters where it happens.
If there's an error in e.g. floating-point unit, it would just cause random errors in the output, but the game would probably keep running. That might be completely fine, if it's rare and you could undervolt just that unit a lot. Especially in somewhere in the graphics pipeline, where it would just generate visual noise. Also, I think energy consumed / heat is proportional to voltage squared, so it has a big effect.
If there's an error in e.g. floating-point unit, it would just cause random errors in the output, but the game would probably keep running. That might be completely fine, if it's rare and you could undervolt just that unit a lot. Especially in somewhere in the graphics pipeline, where it would just generate visual noise. Also, I think energy consumed / heat is proportional to voltage squared, so it has a big effect.