Ran a stress test and woke up to my PC after a reboot

Wait.... Question, what is the offset? 1.130 on an offset confuses me. Did you mean you had it fixed at 1.130v and it did that?

Also, if you're going to stress a new overclock, I suggest watching the temps very closely for the first half hour to an hour. I ALWAYS test with IntelBurnTest for at least 10 minutes before ever doing a long Prime95 stress endurance. If it doesn't overheat under IBT in ten minutes, prime has very little chance to.

Chances are it became unstable and BSOD'd and just rebooted the system. I would do my thermal testing with IBT and watch the temperatures before thinking about an overnight Prime95 session for sure. That way if it is a thermal issue; it'll be evident rather quickly. My 2600k@4.4Ghz with a -0.040v offset (maxes at about 1.25v only hits 63C in IBT for the highest I've ever had it hit. Prime only achieved a 58C on one of my cores in 12 hours. So thermal testing with IBT, endurance stability tests with Prime95. If you get past the IBT, you can pretty much narrow any problems in Prime95 to voltage.

I confused the offset voltage with something else, it was 0.968 I think and the I watched the temps in the first half an hour, it reached 72-75 degrees(one of the cores).
The ASUS AI suite says it's 1.130. I'll edit the original post now.

Whenever you're stressing the CPU, have CPU-Z or another monitor running. That way you can actually see what voltage the CPU is running. If you're using an offset you're still using the chips VID. So the chip will pull whatever volts the VID says it needs. So if you're at a 1Ghz overclock; it will actually ramp up insanely and without offset "could" burn the processor up.

So if you're wanting low idle voltages and speedstep you HAVE to have offset enabled. Easiest way to clock however is running a fixed voltage which will be easier to stabilize a shaky chip at higher speeds.

Alright I see, I did have CPU-Z running during the stress test and it said the Vcore was 1.200~. I can't remember the exact number and sorry if I didn't mention this before, it's just that I'm new to OCing(CPU OCing that is). Got any tips for me on how to set the proper voltage for the cpu?

~1.2v is pretty high for the CPU you have. I hear the suggested absolute max to be 1.3 or so.

The way I'd go about getting your voltage is setting it to fixed and going with something like 1.050v or 1.1v and going from stock and boot up and run IBT for a few runs until you get it to become unstable (bsod or IBT error) Remember keep an eye on those temperatures at all times. IBT will heat that thing up for glory. IBT maxes me at 63C usually and Prime95 after six hours has only hit 56C with my current setup.So if you're wanting a safe limit, don't let IBT go over 75C. If it does, back off on the voltage and find a stable frequency with the voltage that keeps you under 75C with IBT. That should result in Prime temperatures around 70C max. If you want lower temperatures, then let IBT max you at 70C and Prime should only take you to about 65C or so.. I keep under those because of the low voltage my chip wants. Also, I want this processor to stick around for a good many years; so I'm not pushing it too hot with too much voltage.

OK, so let me see if I got it straight, I need to set the voltage to 1.050v or 1.1v and start increasing the frequency of the cpu until it becomes unstable in IBT, correct?

That's how I do it. Then the more adventurous I feel the farther I'll take it in the voltage. Say you get to 4Ghz at 1.1v and 4.1Ghz is unstable and bsods at IBT. You can add a little voltage and usually get the stability to handle that frequency. Sometimes you can even go further on that small of a voltage increase. I just wouldn't recommend going up into the 1.3 range at all. I'd probably limit myself to 1.2-1.25v with that chip.

Thing is though, that I have a clock speed that I aim for - 4.2 Ghz.
So would you recommend testing it on 1.1v with IBT and if I encounter instability gradually increase the voltage until it runs stable on IBT and then test it on Prime95?
Thanks for the help btw  

Yep! Now you're getting it. Let me know how that goes bro, I'm sure you'll get it perfected. Usually I need 0.01 to 0.02v more to last a 24 hour prime than I do a standard set of IBT runs.

Awesome.
last question, if IBT doesn't detect instability or gives me a BSOD rather quickly, how long should I keep it running?

I usually run 10 cycles on high setting which results to about 20-30 minutes. IBT isn't great for stability but it does detect bigger stability issues and it always picks up on heat related problems.

Prime won't run the CPU so hard and won't skyrocket the temperatures as much IBT gives me 63C max while Prime only gets me to 55C. BUT Prime over 24 hours will detect almost any instability you have. 95% of the time for me though, after six hours or so if I haven't had any errors; I don't for the rest of the run. I HAVE had them crash or have an error on one of the workers after it before; but it's rare.

OK, great. One thing still bothers me though.. why did my PC boot up after the stress test that I run..
Anyhow, I appreciate all the help and you for putting up with all of my questions haha
Have a nice day!

Sometimes with a BSOD, windows can actually just reset itself. Pretty neat considering older platforms hardly ever could after such an error.  

Best answer selected by Grach.

Cool, thanks for everything again  

You are welcome!   Keep learning and you'll be able to pull some wicked clocks! Don't forget to get to look at the Intel overclocking sticky!