The limit, as I've understood, is (72 * 0.0125 V) + 0.6 V = 1.5 V, and is set by software. Hardware wise there is no limit. The limit I was referring to was that somewhere Igor said that do not overclock your devices over 500 MHz for constant use. Assuming he meant 500 MHz @ def voltages.

Hmm.. Thank you for this information. I was thinking that is the voltage danger affected by its speed. Would seem logical. So the "danger factor" goes linearly, basically voltage * speed?

Meaning that at default settings its 1.35 V * 600 MHz = 0.81 GVHz?

With my 1 GHz settings it would be then 1.2875 V * 1 GHz = 1.2875 GVHz.

If that is correct then the closest value for 0.81 GVHz would be something between:
700 MHz @ 1.1125 V = 0.77875 GVHz
750 MHz @ 1.125 V = 0.84375 GVHz

And the "safe" limit Igor was referring is then 500 MHz @ 1.2 V = 0.6 GVHz.

The closest settings with my conf would be then:
550 MHz @ 1 V = 0.55 GVHz
600 MHz @ 1.0125 V = 0.6075 GVHz

I'm sure there are other factors, like heat etc, but is the basic logic behind voltages and speeds like this?

In that case I should make new setups. starving550, starving700 and starving1150 in order for ppl who use them can have more reliability with increased speed and decreased battery consumption?

Also, titan, can you comment on the idle frequencies? Is it wise to idle @ 125 MHz? Or should I go for 500 MHz? Or 550 MHz with starving conf, perhaps, as the GVHz rating is lower than default @ 500 MHz? 250 Mhz, as seems to me, has too little voltage difference and 500 MHz wins the day by quickly doing idle tasks and resume to sleep state? Also, wasn't there a some sort of bug @ 125 MHz?