What limits overclocking?

[|Ric|]

I was once told that the thing that limited overclocking was the fact that when the logic gates got hot they didnt work as fast, so this gave you a max overclock

Though I was under the impression that if you gve it enough volts you can just keep cranking it higher and higher, and when you gave it too many volts you fried it. Obviosuly increasing the volts means more heat and if you can't control this you can't keep whacking up the volts as your pass the maximum operating temperature of the core (which I assume permanently damages the chip)

Perhaps someone could offer a more correct view?

Thanks

 

[|Ric|]

so does the gate delay increasing actually provide a real upper bound or is it theoretical? (i.e. the actual problem is heat dissipation and the CPU would burn out before it mattered)