What do the different temperatures mean?

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Profile Dave

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Message 102767 - Posted: 1 Feb 2021, 10:14:27 UTC

It would be good to know what the different temperatures mean.
Psensors gives me
Composite 40 40 40 (value Min Max)
Temp1 30 30 40
Tctl 73 66 80
Tdie 73 66 80
Tccd1 67 64 78

I have found that Tctl and Tdie are basically the same but with some processors there is an offset with some cpus to do with fan control and seem to be the temp at the interface with heat sink but haven't been able to work out what Composite, Temp1 and tccd1 are.

Graphics card and hdd temps are labelled as such so no problem there.

Ryzen7 3700X with Ubuntu 20.10, And the above figures with five cores on 100% plus minor things like browsing internet. It would be useful to know which figure is the one I should be looking at. Cooling is a cheap liquid system.
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Profile Jord
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Message 102768 - Posted: 1 Feb 2021, 10:31:09 UTC - in response to Message 102767.  

Tdie is the actual temperature of the dies.
Tctl is the temperature with offsets.
Composite looks to be SSD temperatures, more specifically NVMe drives.
Tccd1 is temperature of first charge-coupled device. (A charge-coupled device is an integrated circuit containing an array of linked, or coupled, capacitors. Under the control of an external circuit, each capacitor can transfer its electric charge to a neighboring capacitor.)
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Profile Dave

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Message 102771 - Posted: 1 Feb 2021, 10:34:21 UTC - in response to Message 102768.  

Thanks Jord,

I was pretty certain someone would know the answers off the top of their head. That just leaves Temp1.
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Profile Jord
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Message 102772 - Posted: 1 Feb 2021, 10:38:05 UTC - in response to Message 102771.  

Not off the top of my head, but via good searches on the internet. ;-)
I skipped Temp1 as it looks to be a temporary name. But you ought to be able to check that if you click on it, if you run the GUI. See https://wpitchoune.net/psensor/faq.html#S_WhatIsTheSensor (not all links off that page work anymore)
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Profile Dave

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Message 102774 - Posted: 1 Feb 2021, 11:03:21 UTC - in response to Message 102772.  

Thanks,

chip iwlwifi_1 I will look to see if it goes up when BOINC does its 100MB plus uploads or perhaps a better test would be when I download the next version of Ubuntu as I only get100KB/s uploads speed which is hardly going to tax it.
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Profile Keith Myers
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Message 102776 - Posted: 1 Feb 2021, 15:37:54 UTC

Jord and Dave, that is incorrect with respect to Tccd1. With Zen 2 processors. Each 7nm die reports its own temperature. Since the 3700X only uses a single die in the package, you only have Tccd1.
For a 3900X or 3950X, you get Tccd1 and Tccd2 reported.
For my Epyc 7402P, I get Tccd1, Tccd2, Tccd3 and Tccd4 reported since the package contains 4 CCD dies and 1 I/O die.
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Profile Jord
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Message 102777 - Posted: 1 Feb 2021, 16:08:15 UTC - in response to Message 102776.  

Jord and Dave, that is incorrect with respect to Tccd1.
Yes, go say it's incorrect but then don't explain what CCD stands for either.

So I did another search, this time for "CPU CCD dies" and found it stands for Core complex die. (CCD is the physical die that contains the CPU cores, up to 8 of them. Desktop Zen2 processors have 1 or 2 CCDs, Threadripper and EPYC have up to 8.
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Profile Keith Myers
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Message 102779 - Posted: 1 Feb 2021, 16:36:19 UTC - in response to Message 102777.  

Thanks for further explanation of my simplistic and well known answer.
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Profile Dave

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Message 102780 - Posted: 1 Feb 2021, 16:42:39 UTC - in response to Message 102777.  

Makes sense, looking at Psensor Tdie/Tctl lag behind tccd1 by about a second in changes. Even running 16 processors flat out temp is well below the maximum allowed. Interestingly the Tdie and Tctl continue to show spikes if I suspend computation even though the Tccd1 internal reporting from the processor drops to a constant.
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Profile Jord
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Message 102781 - Posted: 1 Feb 2021, 16:43:15 UTC - in response to Message 102779.  

Thanks for further explanation of my simplistic and well known answer.
Well known by whom?
Simplistic yes, I can post a whole long post with all kinds of abbreviations and acronyms and leave it to the reader to go look them up. Is what you did here. Tell us we're wrong, but not tell us what that key ccd in Tccd stands for. Even mention ccd. Are you working with it every day that you can't figure that there may be people on this earth who don't have a clue what you're talking about?
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Message 102784 - Posted: 1 Feb 2021, 17:46:26 UTC - in response to Message 102781.  

I just assumed that an owner of a modern AMD processor, one that has dominated the news for the past three years would be familiar with the term.
It is not some esoteric pseudonym rarely used in computer forums. Very well known in fact.
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Message 102785 - Posted: 1 Feb 2021, 19:40:37 UTC - in response to Message 102784.  

I just assumed that an owner of a modern AMD processor, one that has dominated the news for the past three years would be familiar with the term.
It is not some esoteric pseudonym rarely used in computer forums. Very well known in fact.


Well, it was new to me and while a long way from being an expert, I probably know a lot more than your average user who buys a pre-configured box and if anything goes wrong they pay someone to sort it out. (Unless they have children when they fix it or them!)
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Message boards : Questions and problems : What do the different temperatures mean?

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