Incorrect CPU Temp. sensor on X399 Taichi

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   Hi,

I have recognized that the "CPU Temp." sensor returns incorrect values on the X399 Taichi after updating the BIOS to the last version 3.20. The sensor simply returns 40°C at every condition. Therefore, the reported values will not change if the CPU heats up or cools down.

So, if the fan control is switched form "Tctrl" to "CPU Temp." the fan speeds will not change at all. In addition, it is irrelevant if the standard, silent, performance or custom curve is selected. The fan speed will be stuck at their 40°C value at any condition. The Tctrl otherwise acts as expected but unfortunately with the +27°C offset added.

furthermore, I have read related threads, e. g. for the x370 boards. It seems that they have this specific problem too. For what ever reason, it seems that a incorrect or faulty temperature readout is implemented on all AM4 and X399 boards. Either, because the Tjunction temp. isn't correctly obtained from the CPU or the on board sensor below the socket isn't accecces the right way (if ther is any).

If you have observed the same behaviour, please add your findings.

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jhoffmann Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 18 Aug 2018 Status: Offline Points: 5	Post Options Post Reply Quote jhoffmann Report Post Thanks(0) Quote Reply Topic: Incorrect CPU Temp. sensor on X399 Taichi Posted: 18 Aug 2018 at 7:02pm
	Hi, I have recognized that the "CPU Temp." sensor returns incorrect values on the X399 Taichi after updating the BIOS to the last version 3.20. The sensor simply returns 40°C at every condition. Therefore, the reported values will not change if the CPU heats up or cools down. So, if the fan control is switched form "Tctrl" to "CPU Temp." the fan speeds will not change at all. In addition, it is irrelevant if the standard, silent, performance or custom curve is selected. The fan speed will be stuck at their 40°C value at any condition. The Tctrl otherwise acts as expected but unfortunately with the +27°C offset added. furthermore, I have read related threads, e. g. for the x370 boards. It seems that they have this specific problem too. For what ever reason, it seems that a incorrect or faulty temperature readout is implemented on all AM4 and X399 boards. Either, because the Tjunction temp. isn't correctly obtained from the CPU or the on board sensor below the socket isn't accecces the right way (if ther is any). If you have observed the same behaviour, please add your findings.

ssateneth Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 19 Oct 2017 Status: Offline Points: 129	Post Options Post Reply Quote ssateneth Report Post Thanks(0) Quote Reply Posted: 19 Aug 2018 at 5:44am
	I can confirm CPU (PECI) sensor is locked to 40C on P3.20. However, all other temperature sensors work as expected, including CPU(Tctl), CPU (Tdie), and CPU under the Nuvoton NCT6779D sensor chip. I don't bother with PECI anyways though, its a moot point. I only use Tdie since it is the true temperature.
	MB: X399 Taichi, UEFI L3.32 VGA: EVGA 1080 Ti FTW3 PSU: Seasonic PRIME 1300 W PLATINUM CPU: AMD Ryzen Threadripper 2950X MEM: 4x16GB, 3600MHz G.Skill Trident Z F4-3600C17Q-64GTZKW

fnordie Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 22 Jul 2018 Status: Offline Points: 78	Post Options Post Reply Quote fnordie Report Post Thanks(0) Quote Reply Posted: 19 Aug 2018 at 1:34pm
	i think my x470 fatality gaming k4 has the same problem. http://forum.asrock.com/forum_posts.asp?TID=9207&KW=cpu+temp&title=cpu-temperature-sensor-problem-on-asrock-x470-fata Edited by fnordie - 19 Aug 2018 at 1:38pm

fnordie Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 22 Jul 2018 Status: Offline Points: 78	Post Options Post Reply Quote fnordie Report Post Thanks(0) Quote Reply Posted: 19 Aug 2018 at 5:53pm
	PECI is wrong sensor i think also the PECI sensor is at 40c for me too, but i thing this is wrong CPU sensor. in HWInfo settings enable reading for negative temps. then i have one CPU reading (on motherboard) more but -62 or somithing like that. Edited by fnordie - 19 Aug 2018 at 5:54pm

Pennaith Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 20 Aug 2018 Status: Offline Points: 1	Post Options Post Reply Quote Pennaith Report Post Thanks(0) Quote Reply Posted: 20 Aug 2018 at 10:49pm
	I noticed this issue on my x470 Taichi as well. Attempting to use "CPU" for the fan tuning resulted in the fans never changing speeds even when stress testing and the CPU temp raising. I don't know if I am just misunderstanding what value that is tied to and maybe it isn't hitting the breakpoints I am expecting, but it does not seem to work as expected. I switched to using the tctl for the fan tuning and this seems to be working more as expected. EDIT - Just in case this is a bios issue, I am getting this with v. 1.50. I can't say for certain if it was working prior cause I just built this machine and updating the bios was one of the things I did before really digging into the settings and testing. Edited by Pennaith - 20 Aug 2018 at 10:55pm

jhoffmann Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 18 Aug 2018 Status: Offline Points: 5	Post Options Post Reply Quote jhoffmann Report Post Thanks(0) Quote Reply Posted: 21 Aug 2018 at 8:57pm
	Thank you! I can also read the correct values from the CPU under windows with HWInfo64 - in fact for the Tctl and Tdie. I would assume the program simply subtracts the 27°C offset from the Tctl value here. But, that is not the point here. The problem is that the BIOS will not control the fans by the "CPU Temp." correctly. Therefore, we have to switch to the Tctl in the bios. Unfortunately this value is too sensitive to load changes such that the fans will ramp up and slow down like crazy.

jhoffmann Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 18 Aug 2018 Status: Offline Points: 5	Post Options Post Reply Quote jhoffmann Report Post Thanks(0) Quote Reply Posted: 21 Aug 2018 at 9:09pm
	Well it is definitely broken. Because having a control function that relies on a temperature value that won't change makes no sense. I could imagine that the engineers want to implemented a function here that realizes some kind of filtering to reduces the slope of the fan cure or at least some kind of hysteresis. But it seems that this implementation is broken, providing 40 ° C for "CPU Temp" at least within a human-perceivable time span.

kschendel Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 21 Aug 2018 Status: Offline Points: 86	Post Options Post Reply Quote kschendel Report Post Thanks(0) Quote Reply Posted: 21 Aug 2018 at 10:33pm
	Another me-too, this one is an X470 Taichi Ultimate. I went round and round on this with tech support, almost RMA'ed the board but decided not to since everything else seems to work. I've been running most of the fans from Tctrl. Since i generally run linux, I might set up a specific fancontrol profile to run one or more fans off of one of the other thermistor sensors that actually works, but haven't bothered to date. I had been assuming that my board was broken but maybe this is a generic problem. Very strange. (PS I seem to recall that at least for the X470 Taichi BIOS, you can't select Tctrl in the cute FanTastic graphical thingie, but you can select it in the tabular layout.) BIOS is whatever the early-July Taichi update was. Edited by kschendel - 21 Aug 2018 at 10:34pm

fnordie Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 22 Jul 2018 Status: Offline Points: 78	Post Options Post Reply Quote fnordie Report Post Thanks(0) Quote Reply Posted: 07 Sep 2018 at 9:47pm
	Any news about our issue? Would be nice if someone from ASRock can comment on this?

Kami Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 18 Sep 2018 Location: Canada Status: Offline Points: 2	Post Options Post Reply Quote Kami Report Post Thanks(0) Quote Reply Posted: 18 Sep 2018 at 7:56am
	Yeah, I'm hoping this issue gets fixed as well. I'd very much prefer that my case fans are observing CPU temp instead of TCTRL but if it can't monitor the temps effectively, it's kinda pointless. ASRock X399M Taichi here.