Does OC Panel report Ryzen 1700X/1800X temps accurately, or with a +20 C offset?

[R5Eandme]

I read that Ryzen 7 1700X and 1800X CPUs appear to add about a +20 C offset to the actual temps at the Tctl sensor (die-to-heat spreader junction). AMD purposely does this so the fan control curves will act more aggressively to get out in front of rising CPU temps in response to increased processor demands. But this has freaked out users who see high temps at idle (e.g. 40-50 C) through software monitoring. This is my understanding of the situation so please correct me or add to the post with additional info.

My question: is anyone using OC Panel I or II on a build with Ryzen 7 1700X and 1800X CPUs, and what temps does OC Panel show? Are they accurate (i.e. no 20 C offset)?

Thanks!

[Arne Saknussemm]

It's a 27 degree offset...so yes Tctl can look shocking. 95 degrees Tctl equates to 68 degrees Tdie which is suggested max. Some software applies the offset some does not I guess.

I don't have an OC panel..can't help with that bit

[R5Eandme]

It's a 27 degree offset...so yes Tctl can look shocking. 95 degrees Tctl equates to 68 degrees Tdie which is suggested max. Some software applies the offset some does not I guess.

I don't have an OC panel..can't help with that bit

Thanks Arne,

Do you happen to know which sensor ASUS BIOS uses, Tctl or Tdie, and if the BIOS also might apply the offset?

On my R5E, I noticed that OC Panel worked fine to report CPU temps and CPU fan rpm even before installing an OS. So OC Panel must be seeing what BIOS sees, at least on that platform.

This situation is confusing. especially to me.

[Arne Saknussemm]

Sorry R5Eandme....I'm telling you wrong...the problem is I haven't fired up one of those boards...I'm talking Threadripper offset...you are correct...for ryzen it is 20 degrees

But it's more or less the same deal I guess...here, latest BIOS do the offset thing and report actual temp...so on my MB display it shows idle temps at 23 dgrees...and same in BIOS...I would presume latest Ryzen board BIOS would do the same...

But you know...presumption is the mother of...

gupsterg will know...

[gupsterg]

You guys are correct it will be +20°C on TCTL for 1700X/1800X . Most software monitoring now accounts for it. Some opt to show TCTL and another reading without.



I believe OC panel will show the CPU temperature from Super IO chip (green box). As it hooks into UEFI/BIOS and that is what is shown in UEFI/BIOS "hardware monitor". Initially at launch there were some oddities with this reading, but ~3-6mths in it was all sorted.

Some still are freaked by the sporadic jumps Ryzen exhibits for CPU temps. This is as the CPU has ~20 on die sensors and some rotating goes on plus highest value shown.

[R5Eandme]

Thanks Gupsterg and Arne! I appreciate this difficult to find information. What a great forum.

I looked up "Super I/O chip" on Wikipedia and learned some new things. It apparently interfaces with the UEFI BIOS chip, temp sensors, fan PWM and so on. The fog lifts a little. I am guessing it also participates in the boot process, like maybe writing BIOS into memory? Is this the "System on Chip" or SOC that I've heard about?

[gupsterg]

NP .

The info in this article should cover SOC aspect of Ryzen, link.

The Super IO chip does not write BIOS to memory, it is doing other functionality AFAIK (temp sensors, fan PWM, etc). It does interface with CPU via LPC bus. Only block diagram I could find with relevant stuff was a Gigabyte X399 one .



I'm gonna have to find an ASUS priest to confess my sins now! .

[R5Eandme]

" I'm gonna have to find an ASUS priest to confess my sins now! ."

... and afterwards say a few Hail Mary's (especially while flashing BIOS).

Thanks so much, this is very informative, even if it is Gigabyte.

[gupsterg]

LOL, even the divine may not forgive my sins! .

NP , now you'll get your googlefu in gear some more .