This is the set up I would use.
XMP profile as my mode of OC - this sorts out my memory frequency and settings.
Multiplier set to 42x this allow 4200MHz for your core.
LLC or load level calibration I set at medium or regular, 4 or 5 on some bios options. This provides some flattening out of the Intel design feature vDdroop but still gives me the benefits of that design feature.
Voltage I like to use the offset method. This allows me the full dynamic range of the C states and the luxury of having the upper levels available when under max load.
So voltage mode to offset, then positive offset + and 0.020 as my starting point.
Here after i boot to OS and run some small stress test, and if I pass I leave well alone, if not and I need additional voltage I simply increase the amount of positive voltage.
As a rule of thumb I do not want my 24/7 system to have voltage over 1.420 nor temps at idle/load higher than 30/80'c
It is a good idea not to rely on one stress test alone, nor is it a good idea to cook your CPU for days on end. In my view stress tests have their place in the process but the ultimate test is the real world. If your system does what you want it to do without fault or error then your system is stable.
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