How long do I need to be prime stable for?

[Sampsy]

I'm currently seeing how low I can push my volts on my 2500k overclock and stability testing with prime but I really don't know how long it should be stable for. Speedstep is on so it will be sitting at 1.6Ghz unless gaming and while I may end up gaming for a few hours on end that isn't going to be as stressful as a stability test. How long do you reckon I should go for?

 

[Narj]

By my limited experience, if you're using offset voltage then it's likely that you won't see a crash under load, it'll be when idle. If not, ignore me.

 

[Sampsy]

I am indeed using voltage offset. I'm also wondering about how people test their voltage when posting CPUz pics of their overclock. My 5Ghz oc will pull (at my current UEFI settings) 1.354-1.36v if I am running Prime, but only 1.288 - 1.336 while running Super pi. Is it normal to post voltages when at 100% load? Pi only seems to bring it up to 30-50% on each core.