with a 4+1 (or 4+1) vrm like you have on that board 4ghz shouldnt take any effort what so ever.
-find the cpu vid in core temps and set your voltage to .05 higher
-for instance if your vid is 1.325 set yours to 1.375
-turn on HPC mode if you have it in bios
-turn off cool n quiet (untill your done then turn it back on)
-set your multi to 20x for a start
-boot and use cpu-z to monitor your idle voltage and write it down,
-your idle voltage should be around what you set in bios but is okay if its a little bit above or below (say 0.025 +/-)
-run cinebench and see your load voltage and write that down
-if your load voltage is below your idle voltage you need to go into bios and find loadline calibration, turn this up a notch (wether its a higher percentage or wether its from low-medium), reboot and retest, if your load voltage is too load you may blue screen.
-keep doing that until your load voltage matches your idle.
-your load voltage should not be around 1.5v, it wont damage your chip if it is but its unlikely to be necessary and will results in VRMs throttling which means you're not actually stressing your chip under stress testing.
-assuming you can run cinebench stable without braking 65-70*c run it again while watching clock speeds in coretemp, if lots of them all at once drop down to 2250mhz or 1400mhz that means your vrms are likely declocking, (you will also note your cpu temps are very low if this is the case), if this happens to you try reducing voltage or loadline calibration in bios a little.
-loadline calibration works exponentially with voltage so 1.2v in bios may give 1.2v at load (so +0.0v) with "medium" loadline, but with "high" loadline may give 1.3 (so +.1v)
1.25v in bios with medium loadline might give 1.27v at load (so +.02v) but "high" loadline might give you 1.35v under load (so +.15v), you need to balance them by turning the bios voltage up and down (taking notes) and loadline up and down (taking notes), it sounds really complicated but it isnt its just noticing how it affects things and knowing this helps makes troubleshooting instability and problems allot easier and make it safer too.
run cinebench and if it passes put the multi another higher.
keep doing that until it fails and then turn it 2 or so multi's back.
then use amd overdrive stress test which takes an hour,
assuming you have an overclock now of 4.3ghz or whatever (may be more, may be less) you can be happy or try pushing further, 4.5ghz is plenty fast enough (525ish cinebench on an fx6 and 700ish for an fx8) and the voltages required to go higher usually start to increase temps into haswell territory.
thats my quick and dirty method ive developed over the last 4 or 5 years since i started overclocking phenoms and then fx's.
it doesnt matter what fx you have the process (because the architecture..) is the same.
fx4=4+1/4+2: its fine, got for whatever its so cheap its almost disposable.
fx6=4+1/4+2: dont push to over 4.5ghz unless you're at stupidly low volts like 1.3, 4 easy, 4.5ghz should be the limit, 4.5ghz and 1.4v is probably the max a 4+2 board can handle, if you require more voltage dont risk it and settle for 4.4ghz 1.375v or something.
fx6=6+2vrm (msi 970 gaming etc): 4.5ghz easy, again beyond 4.5-4.6 voltages go up, you wont kill your chip or board but at 4.5-4.6ghz your cpu will last YEARS so dont worry about it, do it then get gaming!
fx6=8+2vrm (gigabyte 970a ud3p etc) you should of got the msi 970 gaming board OR if you ahve a 990fx chipset the money should of been spent on an fx8, this is overkill.
fx8=4+1vrm: it'll run but undervolting is usually a great idea to reduce vrm stress, low vid chips work fine but dont overclock (though ive done 3.5ghz at 1.25v on an 8320 and m5a78l-m/usb)
fx8=6+2 vrm (so msi 970 gaming), ive had mine to 5ghz and cinebench r15 790 score (unstable) at 4.95ghz on this combo, for daily use i recommend no higher than 4.5ghz as pointed out above. while possible the increased voltages and temps aren't worth the extra 200mhz, if it has a vrm heatsink dont worry, a hyper 212 evo is a great cheap bundle for this.
fx8=8+2vrm (gigabyte 970a-ud3p, m5a99x evo r2 etc) skys the limit and if you want to run 4.7-4.8ghz+ you can but this will usually (but not always) a big cooler or h100i or something. i personally just rest easy at 4.5 knowing my temps are in the 60's under stress and 45Ic ish gaming and will work fine for the next 5 years if it has to.