I didn't saw how Haswell work perfect and on stock speed.
Maybe 3.5GHz but even that is hot for our experience and what we see last years.
What I saw is some samples are on 3.9GHz where close to point of throttling.
Net is full of people who have 90C on 3.9GHz if they start stability test and now suddenly easy people start to change way of testing. Last linpack and AVX instructions heat Haswell as crazy.
I'm sorry but last 5-6 years when I came home with CPU first week I start Linx, Prime95, OCCT, than go 3DMark Vantage, Fritz Chess, CINEBENCH and comparing and than if one week everything work OK start OC, again same way LinX(AVX Edition necessary in last time)Prime95, OCCCT with AVX Enable, wPrime, X264, CINEBENCH, ycruncher, ....and that I declare OC and save OC Profil usually 200-300MHz than last clock.
I'm happy now because I have 4.8GHz stable 15h Prime95 and I can 4.5GHz clock for every day, not more....Prime95 is in my experience most required test for Ivy Bridge, harder even than LinX AVX Edition and even temps are 2-3higher and I need 0.0025V more than for LinX only Prime95 Blend test show real temps after
2-3h example maybe even little more.
Everything on side but when you find volttage and clock and Prime95 past 12h 2-3 times and every worker without error you know everything is OK.
I think even 6h is enough. Without drop clock, throttling, temps in border and everything pass, you can confirm with other test and save profil.
OK everything can go wrong after some time special with abnormal high clocks, example over 4.5GHz for 24/7 for my taste is to much. That is 30% enough.
But like I sad you must 200MHz more in stability tests because 100% stability. I do like that.
AIDA64, than my CPU is better than SB 2500K if we look that test as stability or SuperPI, or CINEBENCH.
AIDA64 heat my CPU to 72C on 4.5GHz.
Prime95 is same temp on stock clock.
I mean how big is difference between that two test.