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b450m mobo fan control does not work
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Taxxi View Drop Down
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    Posted: 16 Sep 2018 at 11:26am
I've built my first build with Ryzen 2600X + ASRock B450M Pro4 mobo, and I found out that the cooler & fan speed wasn't following the prescribed value at the UEFI. So here are some tests I've done:


  1. CPU cooler 65% at 50C, 80% at 57C, 90% at 63C, and 100% at 70C, but when testing with OCCT and RealBench, the fan speed doesn't bump up until the CPU temp reaches 82~83C, and it is not even 100% it starts with 80%.

  2. Now if I put 100% at 50C, the CPU fan starts running crazy so I guess the controlling system works at least with the first phase.

  3. I thought the fan controlling system was lagging so I put the CPU temp near 60~70C using RealBench benchmark, but the cooler just remains silent, no speed bumping whatsoever.


So I guess either the HWMonitor is reading a wrong temp or the fan control system is not working, but I think the temp is right (32~34C at idle, -100mv vcore offset). This is really annoying. I tried A-tuning but it didn't work either. I'm using the latest BIOS (ver 1.2).


Any idea or solution would be appreciated. Thanks in advance :)
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datonyb View Drop Down
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Points: 3139 		Post Options Post Options   Thanks (1) Thanks(1)   Quote datonyb Quote  Post ReplyReply Direct Link To This Post Posted: 16 Sep 2018 at 8:08pm
set cpu fan monitoring to 'tctrl' in bios
[url=https://valid.x86.fr/jpg250][/url]

3800X, powercolor reddevil vega64, gskill tridentz3866, taichix370, evga750watt gold
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Taxxi View Drop Down
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Originally posted by datonyb datonyb wrote:

set cpu fan monitoring to 'tctrl' in bios

Thank you sir, I think that might be the cause. I'll definitely try that after my old 2TB HDD successfully moves all the stuff to the new drive... BTW the fans can target the mobo temps just fine, am I correct?


Edited by Taxxi - 16 Sep 2018 at 8:51pm
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Taxxi View Drop Down
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Points: 9 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Taxxi Quote  Post ReplyReply Direct Link To This Post Posted: 18 Sep 2018 at 7:31am
It worked! Thank you!
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DSD27 View Drop Down
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I just got a new Fatal1ty B450 Gaming K4 with the most recent bios and updates. Is this still the case?
What is tctrl and what is the difference from cpu?
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kschendel View Drop Down
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Points: 86 		Post Options Post Options   Thanks (0) Thanks(0)   Quote kschendel Quote  Post ReplyReply Direct Link To This Post Posted: 27 Nov 2018 at 2:32pm
The "monitor CPU" temperature in the BIOS is supposed to be a motherboard thermistor that follows the CPU temp, but outside the CPU package. In effect it's an external CPU temperature rather than an on-die temperature. The advantage of such a thing is that it better reflects the temps that the CPU cooler "sees" and would therefore adjust the fan according to what the cooler heatsink needs as opposed to the die temperature, which fluctuates much more quickly.

Tctrl is a jiggered on-die, inside-the-package temperature. Tdie is the true die temp and Tctrl is Tdie+10C. (Why +10C? because someone at AMD thought it was a good idea.) Running a fan based on Tctrl will ramp the fan up and down more quickly and erratically because it's reflecting the inside the package temperature and not what's soaked into the heat sink.

Apparently this problem is widespread on Asrock boards, and it's seriously annoying. Why they have a sensor source that doesn't work and hasn't been removed or disabled, is beyond me.
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