i7 950 MAX Overclock on air

[rge]

What Unclewebb is saying, is the same discussion we did all have before. Intel specs of 68C Tcase refers to IHS temp, not the cpu diode temp. If cpu diode temp is calibrated at 130W TDP using stock, intel listed variables to read 68C when core temp reaches 100C, then it is calibrated for that one load and TDP and cooling to be cpu specs. But if calibrate it to read 5C away from core temp, it becomes meaningless for intel thermal specs at Tcase. And since CPU temp is rarely going to be accurate, except for one particular TDP, cooling, mobo, etc, it is always going to be significantly less accurate than core temps, calibrated or not.

Most engineering articles will state IC chips should not be run for extended times above 100C, and never above 120C, so not hard to understand intel wanting to measure hot spots and correspondingly set throttling and shutoff. Prior to core sensors, the only way to know if you were running at 100C was assuming gradient through chips were all similar and making guestimates with either IHS temp or with cpu diodes, neither were as accurate as core temps now, however.

So to me, with intel new i7's processors that have fairly accurate core temps even in idle ranges, cpu temp becomes irrelevant. If you look at notebook avg temps, many people, including couple notebooks at work, have core temps in high 80s to 90s constantly for years without issue, some notebooks simply run very hot, never cleaned, etc. While 90's is not my cup of tea, no one has degradation curves to really no what core temp is cut off, other than intel saying cpus are not meant to run near throttling for extended times. It is up to user to guess how far away from throttling.

The only way cpu temps would represent IHS specs, would be to measure IHS and calibrate at one load, or to guestimate at set distance from core temps ie like 30C using stock cooler at max load. But soon as OCing, TDP changes and gradient changes.

Bottom line, intel has two specs. Tjmax of 100C and IHS max of 68C on i7. And these are same specs, ie tjmax of 100C is when IHS = 68C, at set TDP, stock, etc. So 2 reasons to disregard IHS temp, one you cant measure it, 2 it is less relevant than actually using the core temp, now that intel has found way to accurately measure hot spots. And cpu diode temp does not accurately represent either, no matter how it is calibrated. All you can really say is keep tjmax from 100C and that is same thing as saying keep IHS temp from 68C at given TDP,etc

Edit: what is really needed is mttf curves at different volts and temps if one wants to guess at appropriate temps at Ocing volts. Intel had published in past at a now dead link (http://www.intel.com/design/PACKTECH/letter.htm) that the internal goal was less than 1% failure rate of cpus at 7 years, and less than 3% failure at 10 years, and this is for stock settings with stock intel cooler. That included random failures from latent defects and early end of life failure. Which explains why many laptops, despite running near throttling temps, have no issues lasting many years. Even if you start with normal loading temp of 70's and double the mean time to failure for every 15C up to 100C, still less than 4 out of 100 cpus die in 7 years, of course that does not take into account the bigger killer, insane volts. I am primarily interested in lowering my temps for stability. At 4.4 ghz, temps dont mean much, I am stable at 90C or 68C loading temps. But on fringe at 4.6 or 4.7 benching, every 10C dramatically helps stability. As for whether temps of 70C loading vs 95C loading helps slow degradation on one particular highly overclocked cpu (temps to me are irrelevant at stock volts since I wont have it for 10 years), again would love to see mttf/degradation curves at different temps and volts to calculate probability curves...but intel wont be sharing that info anytime soon.