Bro how long should I conduct this test ?

You need to test for stability..... Increase your OC slowly and check for stability each time.... 
Hey, your proc's VID is the same as mine (1.325v) but you get better vcore then mine. Mine need 1.328v (load) at 3.2 Ghz....

Some possible "diagnostics" for the following scenarios under load (my unscientific findings LOL!) :

1) BSOD - Rams not stable, either timings too tight or vdimm not enough or temps too high
2) Shutdown - Vcore or voltage rail unstable, could also be excessive vdroop
3) Hang without shutdown - Could either be rams or vcore, possibly borderline case. It might mean your voltage settings are close to optimum, just need a bit more juice

You are right, perhaps you should follow the advice of some OCers who leave Prime running for at least 24hrs so as to cycle through the day's ambient temps. This is good advice especially if you plan on running your rig 24/7 for folding etc.

Mine, running Prime at 1.39 vcore in Windows for 3.6GHz, typically gets around 60c for hot days and around 52c at night with the aircond running at 27c. But when the water gets hot over an extended period, I typically see an additional 4-5c on a hot day, and about 2c extra at night. My WC setup is not ideal, and the water does tend to get warm if I fully stress the PC for more than 5 hrs at a stretch, which I normally don't so no big deal. I'm a light gamer and usually don't game for more than 3 hrs at a go

IMO 3.6GHz on my 65nm Quad is about the most stable for 24/7 based on my own experience. Last time I even used to run it on a TRUE, temps were higher but still within 70c (but then again, I almost never run my PC with the aircond turned off). Perhaps it was stable also because I had 4 Vizo 120mm fans blowing from the side and a 100CFM 120mm Gigabyte fan (which I salvaged from my 3D Galaxy II WC system) running almost at full power, sucking out the heat from within. My TRUE also had 2 Silverstones in a push-pull config. Imagine the noise pollution!

some said 10 loops equals to one hour OCCT...