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Hot!T junction vs Core Temp

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glocked89
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2020/01/05 11:11:15 (permalink)
Compared to the 9900k of 100c, the Cascade Lake X series only has a T junction of 86c. I was under the impression that T junction was the maximum allowed temp before throttling?

I ran the fpu stress test on aida64 and my cores were throttling at 103c. This scared me and I immediately stopped the test.

After doing some research, it seems as though overclockers and several reviewers are just blasting the 10980xe to get to 4.9-5ghz even reaching temps of 106c and a reviewer from Elmorlabs even stated, "tjmax is 110c".

On hwinfo64, the X299 Dark has a temperature reading called "CPU die" and it seems to be under my core temps by about 20c under load which follows the approximate T junction of 86c.

Is "CPU die" T junction and is the X299 Dark's readings to be trusted? I'm confused
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    jasoncodispoti
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    Re: T junction vs Core Temp 2020/01/05 12:49:32 (permalink)
    The definition of "Max T-Junction" from Intel is as follows...
     
    "Tjunction max is the maximum thermal junction temperature that a processor will allow prior to using internal thermal control mechanisms to reduce power and limit temperature. Activation of the processor's thermal control system may cause performance loss as the processor typically reduces frequency and power to prevent overheating. The goal for a system builder or a do-it-yourself (DIY) end user is to design a platform configuration that keeps the processor under the Tjunction max threshold during heavy workloads to maximize performance of the system. 
    The benefit to a user is that many third-party utilities can monitor the digital thermal sensor (DTS) on the processor die to see how close the system is approaching the Tjunction max temperature without any destructive testing. We recommend that end users look up information on the product specification page (ark.intel.com) to aid them in system assembly. Original design manufacturers should consult the nondisclosure agreement (NDA) documentation available to them for full details."
     
    Yes, T-Junction is the max temp of the CPU before thermal throttling will start to take place. When overclocking there is a lot more to the process than just setting a high frequency and high voltage so that its "stable" performance bench marking most be done to see if there is any actual performance gain. I can only assume that the CPU in the examples you mentioned above were throttling and down clocking to a lower frequency without the end user knowing. 
     
    The "CPU Die" temp provided by EVGA is not the same temp reading as the CPU Core Temp. You want to use the CPU Core Temp... X299 in general does not play nice at temps above 80C. As the temp of the CPU increases more voltage is needed to keep it stable and as the voltage increases the temp rises creating a cascade...  
     
    Also make sure that TJMax is set correctly in the BIOS on the X299 Dark, typically it does not set this correctly and needs to be manually set by the user. If this value is not set correctly the temp readings from applications such as HWInfo64 will NOT be correct. 
     

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    glocked89
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    Re: T junction vs Core Temp 2020/01/05 14:06:38 (permalink)
    Hey thanks for the reply!
     
    Yes 86c seems to be the maximum core temp, but at Tjunction for the the series such as the 9900k, the CPU will definitely throttle. This doesn't seem to be the case with x299 7, 9, and 10th series. The reviews are well documented and the 10980xe seems to hit core temps well past 86c and not throttling at all. This is what led me to believe that T junction provided by intel was different from core temp. T junction by intel is: "Junction Temperature is the maximum temperature allowed at the processor die." and yet the CORE temps are allowed well past 86c with no throttling.
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    jasoncodispoti
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    Re: T junction vs Core Temp 2020/01/05 14:13:46 (permalink)
    glocked89
    Hey thanks for the reply!
     
    Yes 86c seems to be the maximum core temp, but at Tjunction for the the series such as the 9900k, the CPU will definitely throttle. This doesn't seem to be the case with x299 7, 9, and 10th series. The reviews are well documented and the 10980xe seems to hit core temps well past 86c and not throttling at all. This is what led me to believe that T junction provided by intel was different from core temp. T junction by intel is: "Junction Temperature is the maximum temperature allowed at the processor die." and yet the CORE temps are allowed well past 86c with no throttling.




    Core Temp as far as I know represents the "processor die" temperature and is the same value that the processor uses to throttle the system. Do you have links to these reviews/videos showing core temps this high? Would like to take a look to make sure that we are all talking about the same value. 

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    jasoncodispoti
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    Re: T junction vs Core Temp 2020/01/05 14:17:40 (permalink)
    In addition; Surprisingly Max CPU temps can be controlled by the motherboard... If one were to increase this value or if the motherboard was not auto detecting the correct value it would allow the processor to run at say 103C without thermal throttling. The EVGA X299 Dark, is one such motherboard that does not auto detect the correct TJMax value and needs to be set manually. This could explain the results that you are seeing... 
     
    Edit: 
    Just checked my notes, EVGA X299 Dark auto detects my 9800x as having a max CPU Temp of 105C when it should be 95C.
    post edited by jasoncodispoti - 2020/01/05 14:20:58

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    glocked89
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    Re: T junction vs Core Temp 2020/01/05 14:30:48 (permalink)
    https://elmorlabs.com/index.php/2019-11-26/intel-core-i9-10980xe-5-ghz-on-18-cores/
    https://www.youtube.com/watch?v=H0vLYcPa3uk
     
    Here are a couple. Gamersnexus' is quite long but he states that he increased the tjmax to 105 or something to allow for those clocks.
     
    Yes my x299 dark was actually at 103 and I manually changed it to 86c.
     
    Also, because intel has the 10980xe only at 86c Tjunction, have I possibly made some irreparable damage to my cpu going to 103 on some cores?
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    jasoncodispoti
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    Re: T junction vs Core Temp 2020/01/06 12:42:15 (permalink)
    glocked89
    https://elmorlabs.com/index.php/2019-11-26/intel-core-i9-10980xe-5-ghz-on-18-cores/
    https://www.youtube.com/watch?v=H0vLYcPa3uk
     
    Here are a couple. Gamersnexus' is quite long but he states that he increased the tjmax to 105 or something to allow for those clocks.
     
    Yes my x299 dark was actually at 103 and I manually changed it to 86c.
     
    Also, because intel has the 10980xe only at 86c Tjunction, have I possibly made some irreparable damage to my cpu going to 103 on some cores?




    I took a look at the article and while I see the high temp.... only thing I can figure is that either he changed the max temp for the cpu in the bios or the motherboard auto detected the wrong max temp and the user is not aware.... Running a cpu IMO anywhere near 100C is insane, for perspective that is the boiling point of pure water. I have not yet had time to watch the Gamers Nexus video so I can not speak to it yet. I did do some additional research online and confirmed that the max cpu temp for that cpu is in fact 86C which is actually a slight increase over the previous generation. 
     
    As for it damaging your cpu... I have no idea, only thing I can suggest is testing everything at stock settings. 

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    cletus-cassidy
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    Re: T junction vs Core Temp 2020/01/07 19:06:15 (permalink)
    jasoncodispoti
    The definition of "Max T-Junction" from Intel is as follows...
     
    "Tjunction max is the maximum thermal junction temperature that a processor will allow prior to using internal thermal control mechanisms to reduce power and limit temperature. Activation of the processor's thermal control system may cause performance loss as the processor typically reduces frequency and power to prevent overheating. The goal for a system builder or a do-it-yourself (DIY) end user is to design a platform configuration that keeps the processor under the Tjunction max threshold during heavy workloads to maximize performance of the system. 
    The benefit to a user is that many third-party utilities can monitor the digital thermal sensor (DTS) on the processor die to see how close the system is approaching the Tjunction max temperature without any destructive testing. We recommend that end users look up information on the  (ark.intel.com) to aid them in system assembly. Original design manufacturers should consult the nondisclosure agreement (NDA) documentation available to them for full details."
     
    Yes, T-Junction is the max temp of the CPU before thermal throttling will start to take place. When overclocking there is a lot more to the process than just setting a high frequency and high voltage so that its "stable" performance bench marking most be done to see if there is any actual performance gain. I can only assume that the CPU in the examples you mentioned above were throttling and down clocking to a lower frequency without the end user knowing. 
     
    The "CPU Die" temp provided by EVGA is not the same temp reading as the CPU Core Temp. You want to use the CPU Core Temp... X299 in general does not play nice at temps above 80C. As the temp of the CPU increases more voltage is needed to keep it stable and as the voltage increases the temp rises creating a cascade...  
     
    Also make sure that TJMax is set correctly in the BIOS on the X299 Dark, typically it does not set this correctly and needs to be manually set by the user. If this value is not set correctly the temp readings from applications such as HWInfo64 will NOT be correct. 
     





    Somewhat related question on this topic. I just bought an X299 Dark to pair with a 7900X and SLI 1080 tis I found on sale. When stability testing I keep getting reboots without any kind of error, which I thought was the GPUs (definitely not the PSU as I went overkill with the Corsair AX1600i). I had TJMAX in the BIOS set to auto. I'm wondering if the motherboard was automatically rebooting the machine w/o warning because it thought the CPU was hitting TJMax due the bug using "auto." I just set the TJMax to 95 and am retesting. Thoughts on this from your experience?
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    jasoncodispoti
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    Re: T junction vs Core Temp 2020/01/07 20:02:39 (permalink)
    Hmm, hard to say without knowing what temp the CPU was hitting. I would suggest manually setting the TJMax value in the BIOS and than monitoring temps and see if it occurs again... You may also want to take a look at your power supply, unexplained sudden shutdowns like your describing could certainly be a power issue. Adjust the TJMax, monitor temps, and test again... let us know what happens after that.  

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    KrikU
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    Re: T junction vs Core Temp 2020/02/04 11:21:30 (permalink)
    Why is auto setting for Tjmax set to 105 also in my EVGAX299 MICRO2 ? I've once reached this with CB20 Multi test and it started throttling but did not shut down. Now Im just discovering this as topic. Reading x299 OC guide it should be set to 95 for Skylake-X, but I've read that monitoring software may show wrong temperatures when changing it. Intel spec declares only 85 for my Skylake-X 9960x. Is there any truth out there? :) My CPU is doing well, but it would be insane business that default settings can arise any danger to CPU. Latest BIOS update even lets to set this to 110 but I have no idea why hardcore overclockers need that as they have real nice cooling available and high OC needs normal temperatures to my logic.
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    jasoncodispoti
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    Re: T junction vs Core Temp 2020/02/04 13:37:17 (permalink)
    KrikU
    Why is auto setting for Tjmax set to 105 also in my EVGAX299 MICRO2 ? I've once reached this with CB20 Multi test and it started throttling but did not shut down. Now Im just discovering this as topic. Reading x299 OC guide it should be set to 95 for Skylake-X, but I've read that monitoring software may show wrong temperatures when changing it. Intel spec declares only 85 for my Skylake-X 9960x. Is there any truth out there? :) My CPU is doing well, but it would be insane business that default settings can arise any danger to CPU. Latest BIOS update even lets to set this to 110 but I have no idea why hardcore overclockers need that as they have real nice cooling available and high OC needs normal temperatures to my logic.




    TJMax is set by the CPU, in theory the motherboard will read this value from the processor and set the correct value within the BIOS. In practice though MANY motherboards do not read the correct value and end up setting the wrong value in the BIOS. So who is to blame? Who knows and who cars, but I suspect that Intel is at fault. The good news is that EVGA gives you the ability to manually set this value... As far as what TJMax should be set to, ALWAYS use the value that is stated on the Intel website under the official specifications for the processor. I called Intel Support a while back and confirmed that those values listed on the site are the correct values. As far as applications not reading the correct temp value due to an incorrect TJMax value, this is true. However for clarification the BIOS and software based temp applications rely on the TJMax value to calculate the CPUs temp. If the TJMax value is not set correctly than the values being presented in the BIOS and in software are also not correct. 
     
    Let me know if you have any more questions. 

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    KrikU
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    Re: T junction vs Core Temp 2020/02/05 07:04:33 (permalink)
    Alright, thanks for your answers! Many of the new experiences I read about Cascade Lake-X (and X299 in general) are telling they still hold TJMax pretty high, tons of info to read:
     
    https://www.overclock.net/forum/5-intel-cpus/1632870-skylake-x-kaby-lake-x-combined-discussion.html
    https://www.overclock.net/forum/5-intel-cpus/1737048-intel-core-i9-10980xe-5-ghz-18-cores.html
     
    Last topic shows clearly that 105 TJmax automatically is very common and people not realizing at first that it's not meant for long-term use if we really conclude that. Same time, its not been issue anyway - no real complaints. I now myself realize also that AUTO voltage for my CPU is under load 1.3 or even 1.32 volts for some cores that is also a bit high and 1.2-1.25 may be enough with much more lower temperatures as I read from experiences in web. In my case - max non-oc (If I trust EVGA bios auto-detect) multiplier 45 for 2 cores (Turbo Boost 3.0) and 44 for others, and it works. If I look specs for my 9960x there is actually no info at all what is the all-core max speed Turbo Boost 2.0 from Intel! Take a look at LGA2066 wiki - https://en.wikipedia.org/wiki/LGA_2066 
    I don't wanna go really offtopic, I try to read and learn more and Im thinking about writing little guide in some time.
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    jasoncodispoti
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    Re: T junction vs Core Temp 2020/02/06 18:32:25 (permalink)
    KrikU
    Alright, thanks for your answers! Many of the new experiences I read about Cascade Lake-X (and X299 in general) are telling they still hold TJMax pretty high, tons of info to read:
     
    https://www.overclock.net/forum/5-intel-cpus/1632870-skylake-x-kaby-lake-x-combined-discussion.html
    https://www.overclock.net/forum/5-intel-cpus/1737048-intel-core-i9-10980xe-5-ghz-18-cores.html
     
    Last topic shows clearly that 105 TJmax automatically is very common and people not realizing at first that it's not meant for long-term use if we really conclude that. Same time, its not been issue anyway - no real complaints. I now myself realize also that AUTO voltage for my CPU is under load 1.3 or even 1.32 volts for some cores that is also a bit high and 1.2-1.25 may be enough with much more lower temperatures as I read from experiences in web. In my case - max non-oc (If I trust EVGA bios auto-detect) multiplier 45 for 2 cores (Turbo Boost 3.0) and 44 for others, and it works. If I look specs for my 9960x there is actually no info at all what is the all-core max speed Turbo Boost 2.0 from Intel! Take a look at LGA2066 wiki - https://en.wikipedia.org/wiki/LGA_2066 
    I don't wanna go really offtopic, I try to read and learn more and Im thinking about writing little guide in some time.




    It is a fairly common problem... with most of the Intel CPUs not just the X299. Most people just dont know that its an issue because they never check and for most people it will never be a problem even if it is set incorrectly.
     
    Just because someone owns a Ferrari does not mean they can drive fast... 

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    #13
    KrikU
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    Re: T junction vs Core Temp 2020/02/07 01:03:45 (permalink)
    Actually, diggin more in the web -  there is BD PROCHOT that takes responsibility to switch off CPU in case of emergency situation with high temperature. Going beyond TJmax is just speeds up degradation of CPU, with HCC LGA2066 CPU-s have this lower than 4-8 core CPU-s.

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    jasoncodispoti
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    Re: T junction vs Core Temp 2020/02/07 05:59:07 (permalink)
    KrikU
    Actually, diggin more in the web -  there is BD PROCHOT that takes responsibility to switch off CPU in case of emergency situation with high temperature. Going beyond TJmax is just speeds up degradation of CPU, with HCC LGA2066 CPU-s have this lower than 4-8 core CPU-s.





    While BD PROCHOT is what does the throttling, at least in some cases, I am pretty sure it is still relying on a correct TJMax value. High core count CPUs in some cases will have a lower TJMax value than low core count processors, but this is not always the case or at the very least the differences are negligible. For example that Intel Core i7-9800x has a TJMax of 95C (8 cores 16 threads) and the Intel i9-7980XE has a TJMax of 94C (18 cores and 36 threads).  

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    glocked89
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    Re: T junction vs Core Temp 2020/02/10 09:34:08 (permalink)
    Some Intel overclocking engineers did an AMA on reddit and I was actually able to get my original question answered by someone who actually worked on the Cascade Lake X extreme edition processors.
     
    "The 10980xe is a very similar processor compared to the 9980xe and the 7980xe but only has a tjunction of 86c.
    Why is the tjmax so much lower for Cascade Lake X?


    level 2 
    whitesic

    This isn't a concern for Overclocking. We allow TJMax Override up to 110C for Cascade Lake X, which should be an option in your BIOS, and our customers can configure the defaults based on their design goals. At the same time, I would stress that 110C is not a temperature I would want to run at on my personal machine. :)"
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    dmann304
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    Re: T junction vs Core Temp 2021/01/22 09:12:35 (permalink)
    This is becoming to puzzling, seeting that i went through 3 generations of Skylake to settle down , grow some crops, enjoy the oc, and see
    ower temps with probably the last huraa on this platform.  I run the chip now with Tjmax at 86 according the the intel sheets says too, and sems
    to work good at 48, been down the oc road much on here, with alot of good help, and see that i now can enjoy it at 1.27v cpu, and VCCIN at 1.8v
    stock and a mesh of 30, which i discovered that was stable at, 32 seems to kill tests, so happy their.  but i do get throttling red message in aida64 
    stress, and when i test avx sets with intel XTU, it says i PMAX throttle, even though temps are well in ow 80's under loads, and CPU ID hwinfo says 
    im safe.
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    KrikU
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    Re: T junction vs Core Temp 2021/01/27 05:41:07 (permalink)
    I have set now my Tjunction in bios to 95 degrees because I use long all-core workloads like video rendering with Premiere that can take up to 15 minutes for 30 minutes of 1080p60 video with 16-core 9960x. It will stay nice in 95 degree limit and dynamically lowers clocks a bit to stay at that temperature range.
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