im using 2600k Sandybridge (SB i.e. lga 1155)
from what i understand, the main idea is:
step 1. decide on the multiplier (for me its 40x to reach 4ghz)
step 2. decide if its for "all cores" or for "per core" (for me, its for all cores)
step 3. select LLC as middle (3/5 for asrock mobo, 5 or 6 /10 for asus mobo) why middle is just a rough gauge, u dont want too much or too little for now, anyway LLC can come back to tweak later. (btw u shld understand that LLC is to counter the effect of vdroop)
step 4. select manual voltage mode, set a suitably low vcore voltage (for SB @4ghz can try 1.2v), reboot, if cannot reboot then set abit higher until can reboot
step 5. stress test, if bsod, then go back to step 4 and set abit higher vcore. if no bsod, then during stress test, note down the vcore value shown in cpuz under 100% load, and at the same time note down the VID value shown in realtemp under 100% load [click on the realtime running stopwatch icon in realtemp until it shows VID]. the difference between vcore and VID is the offset. from what i have gathered, generally for SB, below 4.5ghz, the offset is negative i.e. for example the chip wants 1.24v as VID but i supply it with only 1.2v as vcore so the offset is minus0.04v
step 6. now u have a rough idea what the offset should be. note that its just a rough value, not the optimal one yet. now, go into bios, switch to offset mode, then dial in this offset value, then reboot and stress test again, during stress test, note down the vcore (not VID). this vcore value during stress test should be near the vcore u arrived at, by the time u reach step 5.
there are many other parameters to fine tune. for eg. i enable speedstep, enable EIST C1, but disable c3, c6 deep sleep states, enable PLL, keep ram timings at auto, etc. u need to slowly n gradually tweak until no bsod, low enough vcore, load temps low enuf, all at the overclocked speed u target at. for SB, 4to4.4ghz, vcore shld not exceed 1.25v, for 4.5 or 4.6ghz, vcore shld not exceed 1.35v, etc etc these are just approx guideline values, actual performance really depends on ur chip and the quality of all ur other components mobo, psu, cooling, etc unfortunately i am not sure of what the guideline vcore values are for haswell lol u got to slowly google for the relevant info
and TS i strongly suggest u go back to 4ghz first, nail down everything before jumping back to 4.2ghz, no offence, just suggesting a slow but steady approach gd luck also if anyone can spot any mistake i made, pls kindly correct me, im also learning as well lol