E7200 overclock

Hi guys, I have e7200@3.53Ghz for over a year now. Motherboard is gigabyte p45 ud3lr. I'd say it's an excllent sample. I overclocked it straight to 3.5ghz a year ago and the processor got an automatic vcore increase (according to cpu-z to 1.264) Now, i decided to push it a little further and overclocked it to 4Ghz (do not wish more because the processor is running on a crappy box cooler) In order to keep it stable at 4.01Ghz i had to increase vcore manually in bios to 1.39375v. The problem is, i don't know the real vcore. Although i set vcore to 1.39375v, upon reboot bios Health section reads vcore 1.36v Cpu-z also reads the lower value then the one i manually set.

What CPU core voltages to believe? The one i set in bios or the one Bios reads afterwards, or none of them? Intel processor specification says that max safe vcore for this processor is 1.3675, and i would like to obay that. If i am to listen to what my Bios health section says or what cpu-z reads, i am ok. However, if the vcore is what i set it to be (1.39v) i'd rather lower the clock.
Tnx for advice

BIOS readings can be surprisingly accurate on vcore, but CPU-Z is normally far from the truth. In all honesty just increase it to where it's stable or if you're not happy at the temperature take it down a bit, along with the clock.

The safe vcore given by Intel is not a hard rule, technically increasing the clocks isn't safe either and any vcore over stock is pretty unsafe. Overclockers don't really care though, try to keep it below roughly 1.45v or so and all should be grand.. 1.5v would be a bit much for stock cooler. Many people have run more though, I wouldn't worry about the voltage so much, it's the heat that's going to cause you problems first