what vcore you running?
press f8 and choose disable automatically restart on system failure. u can set this in advanced system properties too

hw wise is top notch liao, doubt cooling is d problem. can do a dos based memtest mebe? paiseh, i'm a beginner too when it comes to intel oc... 

manage to get 4.1GHz with 1.275v under stable .
Before tried, get 4.2ghz with about 1.35v and can get 4.3 4.4 with boot to window but cannot get stable even 1.4v... so give up.

Seems i get a unlucky silicon T_T

G3258+asrock b85 killer+seasonic g-550

(before used enermax liberty 400w, i thought maybe power supply old and unstable but after changed is da same T_T)

Seems like ur proc bad than mine.
I can boot with 4.4ghz but not stable even at 1.375v, didnt try out limit of proc.
Currently running 4.1ghz @ 1.262v with 68'c under prime95 stress test, low temp thanks to lovely Xigmatek DarkKnight under silent fan mode
(Max fan speed get lower 2'c but not much different ~ impressive hsf effective.)

I got another same rig for my friend, he got the chip made from costa rica than my proc made from malaysia ~
Start get overclock to 4.1ghz smoothly around 1.1v ~ and get 4.4ghz at 1.250v (didnt try the sweet spot) but because of intel hsf, it get 87'c under prime test. (Seems like a nice hsf r really different much with intel hsf)
Finally i stopped at 4.2ghz @1.160v because get safe temp of 75'c under stress test.