78 i got that when damaged cache(blasted some 1.8V on air to see how much does it take),setting dram clock period 1-14 does not damage the cpu,altough gains are minimal,usually a value around 5-8 is good,but lower you go in this you have to increase vcore.low trfc does not damage also,you get rainbows from graphic corruption resulted from memory errors.

I had tested so far about 5 cpu's,one on dice.

Endurance test consisted seeting vcore 1.6,cache voltage 1.6 and vccsa 1.6(all on air,28 degrees ambient).Also disable vrm protections.Ran like these for hours,basically 32M some 2001,stuff.Got back to previous know settings,all good to go.0 degradation.Did this with 2 cpu's i was going to rma anyway.

On dice i went max with 1.8Vcore and 2.4VCCIN.Only for 2d tests and some 2001,temperature about -70 degrees.Ran for hours straights,0 degradation,no deaths.Truth is i did not test 4c8t intensive benches,this could be harmfull to them.

The way i see it,haswell cpu's are not that sensitive or it's either me i got some tough bastards over here