[UNIQUE] Which of these 3 (identical) CPUs would last longer?

ok so this is a unique topic which (oddly) has never been addressed before in the history of overclocking - or even in the history of internet for that matter - so googling this up is useless, and it's safe to assume that very very few people in the world know the correct answer to this conundrum

so this is the question

suppose we have 3 new & perfectly identical CPUs (for argument's sake, suppose it's an intel 4-core CPU, if that makes a difference)

1- first CPU : stock settings (non-overclocked, non-overvolted), cooled by the standard crappy stock intel heatsink-fan, and has an average idle temperature of 55°C

2- second CPU : heavily overclocked (say by 50%), heavily overvolted, BUT also cooled by a state-of-the-art space-age cooling system so that despite the overclocking it has an average idle temperature of only 35°C

3- third CPU: under-clocked, under-volted, cooled by standard intel cooler, and has an average idle temperature of 35°C (so same temp as the #2 overclocked one: it's underclocked to compensate for the crappy cooling)

btw I mention idle temps but let's assume that there's the same differences in load temps (so CPU #2 & #3 have a -15°C lower average load temp than CPU #1)


question1: assuming they have the same total amount of activity & idle/load time,
which of these 3 CPUs will have a longer lifespan?
(or to reformulate: in which of these 2 CPUs will electro-migration occur first?)

question2: will CPU #2 & CPU #3 have the same lifespan?

PS. since this sort of problem has never been tackled before I reckon only an extremely highly qualified engineer/scientist would know the right answer to this, hoping some of them are on this forum, this question is addressed at them

btw I ask this in the intel section cause the general CPU section seems almost abandoned so unlikely many people will notice this topic

I'm fairly sure this topic has been discussed at least a few times. 55c on an Intel processor is nothing, but my answer would be the same if you said it was run at 95c. The higher voltage degrades the gates faster (electron migration, if I remember correctly), so your second theoretical processor will die first.

However, by the time the second one dies, modern processors will be substantially faster and you would have likely replaced it already.

ok thx so in other words temperature ain't the only factor affecting migration & lifespan?
(voltage in & of itself is dangerous regardless of temperature?)


I ask this cause I wanna buy a 2nd hand CPU, however that #$%$ owner said he couldn't resist the temptation to overclock it heavily (I assume he over-volted it too) but he also swears he water-cooled it really well, so now I dunno if the CPU is still in good condition or not & if it's worth buying :/

I would find out what settings he used, add in the price, and compare to other processors you can get. If the processor is somewhat new (last few generations), it will likely be fine and run for quite a few years.

I'm not sure what you mean by "overclocked it heavily" on water I understand and it still has it's limitations. Second hand is always a gamble but you know the history of this CPU unlike one you may buy from Ebay that has seen 1.8v plus under extreme cooling. Odds are the CPU is fine

so now I dunno if the CPU is still in good condition or not & if it's worth buying :/

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The only used CPU I would NOT buy is one that has been abused under sub ambient cooling methods like LN2, SS, and Dry Ice. As thideras said, these CPUs shut down before any damage can be done on the thermal side of the house.

thideras said:

I would find out what settings he used, add in the price, and compare to other processors you can get. If the processor is somewhat new (last few generations), it will likely be fine and run for quite a few years.

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it's just a 1st generation icore cpu (i5 750), I only wanna build a small rig
he claims it was overclocked to 4ghz without problem (compared to stock 2.6ghz or something). regardless of cooling used, I assume this is only possible with overvolting no?

I assume this is only possible with overvolting no?

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Likely, yes... however, its not a big deal (see how others have responded).

EarthDog said:

Likely, yes... however, its not a big deal (see how others have responded).

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I dunno, Thideras' first post somewhat freaked me out a bit :/
(basically his response implies that CPU 2 & 3 won't have same lifespan...is that right?)

pulverizor said:

I dunno, Thideras' first post somewhat freaked me out a bit :/
(basically his response implies that CPU 2 & 3 won't have same lifespan...is that right?)

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That is right, but nobody would know if it lopped off days/weeks/months/years. People here and everywhere have overclocked CPUs pretty heavily on their daily PCs and they last YEARS. Who knows what the SAME CPU (as each are different) would have done had it not been overclocked. You could buy new and have it crap out on you.

The bottom line is, generally, if someone uses too much voltage, the CPU will protect itself because too much voltage = heat. It really is a non issue outside of known sub ambient abuse where the voltage goes REALLY high.

Lol, these processors have a life span of sooo many hours, youll long upgrade before one where to actually die. Especially if used as intended.

In most cases the mother board ram and psu dies first... Not in any particular order for that matter.

EarthDog said:

That is right, but nobody would know if it lopped off days/weeks/months/years. People here and everywhere have overclocked CPUs pretty heavily on their daily PCs and they last YEARS. Who knows what the SAME CPU (as each are different) would have done had it not been overclocked. You could buy new and have it crap out on you.

The bottom line is, generally, if someone uses too much voltage, the CPU will protect itself because too much voltage = heat. It really is a non issue outside of known sub ambient abuse where the voltage goes REALLY high.

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I guess the real question I meant to ask is, is heat the only factor (for a given quality & amount of activity of the CPU) when it comes to lifespan? if not then it's far more complicated then I thought if a colder but over-volted cpu would last less long than a hotter but non-overclocked cpu, this would mean that heat is only a minor factor?

that's why I assumed that all 3 CPUs are identical (down to a subatomic level, for argument's sake ) and have been subjected to same tasks & activity

ShrimpBrime said:

In most cases the mother board ram and psu dies first... Not in any particular order for that matter.

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my PSU is a Corsair with all-japanese capacitors and my ram is a gskill ripjaws with huge heatsinks (dont intend to overclock them) - not sure they'll kick anytime soon!

Its heat and voltage. There are also silicon considerations as well... as I said every single CPU, even the same model, are different as they come from different parts of the wafer. Some are more leaky (electrically) than others.. some can overclock to the moon, others not so much.

As we alluded to, this is a good exercise, however the deep dive for your uses is good for educational purposes, not so much for which CPU will last longer as there really isn't an answer for that.

EarthDog said:

Its heat and voltage. There are also silicon considerations as well... as I said every single CPU, even the same model, are different as they come from different parts of the wafer. Some are more leaky (electrically) than others.. some can overclock to the moon, others not so much.

As we alluded to, this is a good exercise, however the deep dive for your uses is good for educational purposes, not so much for which CPU will last longer as there really isn't an answer for that.

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alrite so just so we're 100% clear: voltage by itself (regardless of how much cooling) is also a factor?


if so could some1 explain how a very high voltage damages even a very "cold" cpu despite the lack of heat??

(this question never been addressed before AFAIK, every topic on overclocking safety only mentions heat as the danger factor, voltage is only mentioned as one of the factors causing heat)

pulverizor said:

alrite so just so we're 100% clear: voltage by itself (regardless of how much cooling) is also a factor?


if so could some1 explain how a very high voltage damages even a very "cold" cpu despite the lack of heat??

(this question never been addressed before AFAIK, every topic on overclocking safety only mentions heat as the danger factor, voltage is only mentioned as one of the factors causing heat)

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Voltage, by itself, is damaging. The gates in the processor will degrade faster with higher voltage, regardless of temperature.

pulverizor said:

alrite so just so we're 100% clear: voltage by itself (regardless of how much cooling) is also a factor?


if so could some1 explain how a very high voltage damages even a very "cold" cpu despite the lack of heat??

(this question never been addressed before AFAIK, every topic on overclocking safety only mentions heat as the danger factor, voltage is only mentioned as one of the factors causing heat)

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Its been covered before, but its more basic electrical engineering knowledge applied to this context. There is also a reason why there are voltage limits for daily overclocks.

Voltage is electrical PRESSURE. The more voltage you use, the more PRESSURE is going through those gates/that piece of silicon. The cold slows things down or adds more resistance to that pressure, hence allowing one to push more voltage through with less chance of damaging the silicon... that is, if I understand things correctly.

thideras said:

Voltage, by itself, is damaging. The gates in the processor will degrade faster with higher voltage, regardless of temperature.

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EarthDog said:

Its been covered before, but its more basic electrical engineering knowledge applied to this context. There is also a reason why there are voltage limits for daily overclocks.

Voltage is electrical PRESSURE. The more voltage you use, the more PRESSURE is going through those gates/that piece of silicon. The cold slows things down or adds more resistance to that pressure, hence allowing one to push more voltage through with less chance of damaging the silicon... that is, if I understand things correctly.

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bummer...so no cooling can fully compensate for extra voltage - no matter how cold??

No cooling can compensate for any voltage for that matter. Look at it like erosion inside the CPU high volts and temps just make it erode faster. High volts low temps noat as fast but still faster than under ideal circumstances.
Your CPU starts dying the day it is first turned on.

Just like humans, where there is life, there is certain death. Even at stock speeds and voltages with temps under control CPUs will die from any number of reasons...

... hence why we gave some high level info of 'not to worry about it unless they abused the CPU under LN2' or something of the like.

EarthDog said:

Its been covered before, but its more basic electrical engineering knowledge applied to this context. There is also a reason why there are voltage limits for daily overclocks.

Voltage is electrical PRESSURE. The more voltage you use, the more PRESSURE is going through those gates/that piece of silicon. The cold slows things down or adds more resistance to that pressure, hence allowing one to push more voltage through with less chance of damaging the silicon... that is, if I understand things correctly.

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Temp is directly corrolated with resistance. Temp rise = resistance rise. Silicon is special as it has a negative temp coefficient. So as temp rises, resistance goes down.