The AMD spec for ABSOLUTE MAX CONDITIONS is "max OPERATING voltage + 0.5V" which is the same as 1.85V +0.5V = 2.35V. For overclocking, if you can handle the resulting heat, I wouldn't go any higher than half the 0.5V adder or 2.10V .
I have a 1.1GHz TBird but plan to try lower Vcore for overclocking 1st since some have made it work and it will also help keep temps down since power formula is c*(V*V)*f where c is a constant, V = voltage, and f = freq. Since V is a squared function, going from 1.85V to 1.65V saves 20% in power (heat)!
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