Whats the long-term damage to CPUs?

[skywalk]

Having recently set a "daily-use" stable OC from 2.66 to 3.78ghz on my i7 920, I'm starting to wonder and worry about long-term DURABILITY of my CPU.

Will my actions in anyway affect the longevity of my CPU? Or will it decrease its lifespan?

Should I leave it at 3.78ghz, or should I bring it down because it will "wear out" my CPU faster?

thanks

 

[nforce4max]

It all depends on voltage and temperature.

 

[skywalk]

thanks...care to elaborate a little?

 

[nforce4max]

thanks...care to elaborate a little?

Higher the voltage greater the heat and greater the electromagnation that weakens the transistors thus the life span of the chip. Normal speeds they can last for decades but at higher than designed and they will gradually fail to ware they are no longer stable at high speeds thus downclocked to normal or lower clocks. CPUs rarely fail unlike ram or drives then boards have a very high rate of failure after several years. Graphics cards tend to fail very easily at high temps but are hard to predict.

 

[CompuTronix]

... electromagnation ...

The term is "electromigration". The following article from Anandtech explains Processor Degradation: The Truth About Processor "Degradation" - http://anandtech.com/cpuchipsets/intel/showdoc.aspx?i=3251&p=6

If your overclock settings don't exceed Intel's voltage and thermal specifications, then your processor will be fine.

All Core i7 9xx variants:

Vcore Max 1,375
Tcase Max (CPU temperature) 68c
Tjunction (Core temperature) 73c

 

[skywalk]

CompuTronix,
I am using core Temp 0.99.5....do those temperatures listed measure Tcore or Tjunction?
on my overclock, I think I hit 67C max, with an OC of 3.78ghz (from 2.66) using prime95

 

[CompuTronix]

... Tcore or Tjunction?...

The terminology is "Tcase" or "Tjunction". This is obvious from my previous post, but I'll spell it out for you anyway:

Tcase = CPU temperature
Tjunction = Core temperature

From the Core i7 and Core 2 Temperature Guide - http://www.tomshardware.com/forum/221745-29-sticky-core-core-temperature-guide


"Section 1: Introduction

Core i and Core 2 processors have 2 different types of temperature sensors; a CPU case (not computer case) Thermal Diode centered under the Cores, and Digital Thermal Sensors located on each Core. The case Thermal Diode measures Tcase (Temperature case), which is CPU temperature, and the Digital Thermal Sensors measure Tjunction (Temperature junction), which is Core temperature. Since these sensors measure 2 distinct thermal levels, there is a 5c temperature difference between them, which is Tcase to Tjunction Gradient. Core i7’s / i5’s and Core 2 Quad’s have 1 Tcase and 4 Tjunction sensors, while Core 2 Duo's have 1 Tcase and 2 Tjunction sensors ...

... The monitoring utilities provided by motherboard manufacturers monitor CPU temperature, while some popular freeware utilities monitor Core temperatures ... Real Temp ... is recommended for users interested in monitoring Core temperatures only ... SpeedFan monitors Tcase (CPU temperature) and Tjunction (Core temperature) ... "

using prime95

Which torture test? Blend? Large FFT's? Small FFT's? There's a difference. Please be specific.

 

[skywalk]

small fft's. Tcase was a typo sorry.
anyway, I think the program core temp measures Tjunction correct?

 

[CompuTronix]

I think the program core temp measures Tjunction correct?

... Core i7’s ... have 1 Tcase and 4 Tjunction sensors...

Get it?

 

[skywalk]

unfortunately, no sorry.

Core Temp lists something like:

Core #0: 30C
Core #1: 31C
Core #2: 30C
etc...all the way to Core #8:

those temperatures are what i'm talking about. in the program itself.

 

[CompuTronix]

unfortunately, no sorry.

... Core i7’s ... have 1 Tcase ... sensors...

 

[skywalk]

Hi Computronix,

i'm sorry but i'm totally not following you at all.

My question is: what temperature measurement is the program core temp displaying?

your answer is to list out the number of sensors within the Core i7, which doesn't answer my question.

i totally don't follow. you've already told me twice, how many sensors the i7 has, but i dont see its relation to the software. please enlighten me

 

[CompuTronix]

My question is: what temperature measurement is the program core temp displaying?

skywalk,

The name, Core Temp, makes the answer obvious. You could've clicked on Core Temp's Help, or read my Guide, but since you're asking, then for everyone's benefit, here's the BIG picture!

Tcase:

There is a single (just 1) Analog Thermal Diode integrated into the substrate layers of the processor package (CPU case ... NOT computer case). This Diode is located dead-center under the Cores, not in, on, or near any individual Core. This device measures Temperature Case or Tcase, which is the overall temperature of the entire CPU package, or "case" that you removed from Intel's retail box and placed in the motherboard's socket. The Diode is sampled and digitzed by the super I/O (Input/Output) chip on the motherboard, and is displayed in BIOS and in temperature monitoring utilities programmed to display CPU temperature. This is why you only see a single (just 1) CPU temperature in BIOS, and not 4 Core temperatures. The accuracy of CPU temperature depends upon how accurately BIOS was programmed by the manufacturer. Inaccuracies are sometimes corrected in later BIOS releases, but are seldom exact due to variables such as after market coolers, overclocking and high Vcore. This is why I developed a procedure for my Guide to calibrate CPU temperature.

Tjunction:

Each individual Core has a Digital Thermal Sensor (DTS) which is comprised of an array of Analog Thermal Diodes that measure the hot spots on the Core. The array is sampled and digitzed by the DTS, and is displayed in temperature monitoring utilities programmed to display Core temperatures. The DTS is read directly from the Cores, and is NOT available in BIOS. This is why you do not see Core temperatures in BIOS. The accuracy of Core temperatures depends upon how accurately the DTS was calibrated by Intel. Inaccuracies are common between Cores due to variables such as sensor slope error, linearity and response scaling. This why I developed a procedure for my Guide to calibrate Core temperatures.

HyperThreading:

i7 processors which have HyperThreading (HT) disabled in BIOS will display 4 Core temperatures in monitoring utilities programmed to display Core temperatures, just like any Quad Core. However, i7 processors which have HT enabled in BIOS may display their 4 physical Core temperatures and 4 virtual Core temperatures (8 Cores total) in some temperature monitoring utilities programmed to display Core temperatures. Since the 4 virtual Cores are essentially a mirror image of the 4 physical Cores, it is not necessary to monitor them. It is instead advisable to disable the 4 virtual Cores in monitoring utilities which allow you to do so, since monitoring 8 Cores is often cumbersome and confusing.

From my Guide:

Section 4: Thermal Flow

Heat originates within the Cores, where Tjunction sensors are located on the hot spots of each Core. Most of the heat dissipates from the top of the Cores through the Integrated Heat Spreader and CPU cooler to air inside the computer. Some of the heat dissipates from the bottom of the Cores through the CPU case, which creates a 5c thermal Gradient toward the center of the substrate, where the Tcase sensor is located. This heat then dissipates through the socket and motherboard to air inside the computer. Safe and sustainable temperatures are determined by CPU cooling efficiency, computer case cooling efficiency, Ambient temperature, Vcore, clock speed and Load.

■ Tjunction is higher than Tcase.

■ Tcase is higher than Ambient.

Tcase and Tjunction:

Real Temp and Core Temp monitor Core temperatures ONLY. Freeware temperature monitoring utilities are available which display CPU temperature and Core temperatures such as Hardware Monitor and SpeedFan. Hardware Monitor can NOT be calibrated, however, SpeedFan can be calibrated for CPU temperature and each individual Core temperature, and can display however many of the 8 Cores for the i7 you desire, both physical and virtual. I use SpeedFan. During normal use I monitor CPU, Core 0, Northbridge and GPU temperatures only. When testing and calibrating, I monitor CPU, Core 0, 1, 2 & 3, Northbridge and GPU, but never Core 4, 5, 6, & 7.

I hope this helps you to understand how temperatures work. If you'd like to learn more, then click on the link in my signature.

Comp

 

[skywalk]

Hi CompuTronix,

Thanks for your patience in answering my questions. This stuff does not come as easily to me as it does to you.

Its strange though, cus it feels like I asked "how do you make orange juice with this orange flavored powder"

and instead of saying "just add cold water," you went into the complex process of how oranges are plucked, chemicals added, drying done, how chemicals are created, what forms molecular bonds, ionic bonds, how water has hydrogen bonds, what bonds are stronger and which ones are weaker.....and made it way too complicated for me to understand!

But after reading and re-reading, I think I figured out the answer to my question: the program CoreTemp measures Tjunction, and Tjunction are hotspots on each core.

Answered in 1 line!

I frankly didnt need to read about DTS, hyperthreading, 5C temp difference, analog thermal diodes, digitizers, or sensor slope error, linearity and response scaling.

It's absolutely chivalrous of you to offer the big picture to me, but I would have been happy with that one-liner that I typed. In fact, i'm still puzzled at the fact that when I asked if the program measured Tcase or Tjunction, you replied by telling me how many sensors the i7 has. Thats like me asking "whats the temperature outside today?" and you reply with "there are 4 thermometers in the bag, and each can measure from 0-100C"

Thanks for teaching me about reading stickies. May I also suggest to you that you read the OPs question first, before spending so much of your precious time typing such painfully detailed computer jargon, when the question could in fact be answered with 1 line. Or in my case, 1 word: Tjunction.

In all fairness, what you posted was still a great read, so thanks for that

 

[skywalk]

The term is "electromigration". The following article from Anandtech explains Processor Degradation: The Truth About Processor "Degradation" - http://anandtech.com/cpuchipsets/intel/showdoc.aspx?i=3251&p=6

If your overclock settings don't exceed Intel's voltage and thermal specifications, then your processor will be fine.

All Core i7 9xx variants:

Vcore Max 1,375
Tcase Max (CPU temperature) 68c
Tjunction (Core temperature) 73c

Any rough idea how going over 73C on Tjunction would affect the overall life of the CPU?
what IS the average life of a CPU anyway? 3 years? (thats how long my warranty is I think)

and if I reach temperatures hotter than 73C, it would reduce its life by weeks/months/years?

thanks, I think this answer was the best, and exactly what I was looking for

 

[CompuTronix]

I frankly didnt need to read about DTS, hyperthreading, 5C temp difference, analog thermal diodes, digitizers, or sensor slope error, linearity and response scaling ... May I also suggest to you that you read the OPs question first, before spending so much of your precious time typing such painfully detailed computer jargon, when the question could in fact be answered with 1 line. Or in my case, 1 word ...

I read your response as a slap in the face with a smile.

I do read questions thoroughly, as well as the entire thread. When I write an explanation, I have in mind the following:

(1) Other forum members are in the background reading without offering comments, so others may benefit from a thorough explanation.

(2) As an engineer, I appreciate that more information is better than less, so nothing remains vague, ambiguous, or open to interpretation.

(3) If I don't include plentiful details, then additional questions are sure to follow.

If there's a question somewhere in your above post concerning Processor Degradation, then perhaps another forum member more succinct than I would be willing to help you.

Comp

 

[skywalk]

 

[C00lIT]

Hi CompuTronix,
Its strange though, cus it feels like I asked "how do you make orange juice with this orange flavored powder"

and instead of saying "just add cold water," you went into the complex process of how oranges are plucked, chemicals added, drying done, how chemicals are created, what forms molecular bonds, ionic bonds, how water has hydrogen bonds, what bonds are stronger and which ones are weaker.....and made it way too complicated for me to understand!

Too funny.

I read your response as a slap in the face with a smile.

I do read questions thoroughly, as well as the entire thread. When I write an explanation, I have in mind the following:

(1) Other forum members are in the background reading without offering comments, so others may benefit from a thorough explanation.

(2) As an engineer, I appreciate that more information is better than less, so nothing remains vague, ambiguous, or open to interpretation.

(3) If I don't include plentiful details, then additional questions are sure to follow.

If there's a question somewhere in your above post concerning Processor Degradation, then perhaps another forum member more succinct than I would be willing to help you.

Comp

Thanks for the details, I learned plenty

 

[CompuTronix]

You're welcome.

 

[RJR]

(2) As an engineer, I appreciate that more information is better than less, so nothing remains vague, ambiguous, or open to interpretation.

OK, just the person I'm looking for, just a quick question for you.

Has Intel published any schematics on vcc pad routing of their processors or package diagrams? I don't know if the processor package uses any power planes or if each individual vcc pad is routed separately or ganged or what. Just something I'm curious about, can't seem to find an answer around.

 

[CompuTronix]

Without a nondisclosure agreement, I haven't found any available schematics, however, Intel's Core i7 9xx Datasheet - http://download.intel.com/design/processor/datashts/320834.pdf - shows an explanation in Section 2.2 "Power and Ground Lands".

 

[xbonez]

@CompuTronix: loved yout explanation of temperature sensors in the CPU case and cores. thanks a lot for that info.

 

[CompuTronix]

You are also quite welcome.