Cool temperatures when at max work but VERY hot when not.

Message boards : Questions and problems : Cool temperatures when at max work but VERY hot when not.
Message board moderation

To post messages, you must log in.

AuthorMessage
Wartem

Send message
Joined: 12 Sep 21
Posts: 2
United States
Message 105414 - Posted: 15 Sep 2021, 19:23:57 UTC
Last modified: 15 Sep 2021, 19:50:49 UTC

Hey,

I think this is very weird:
At 100% CPU utilization (all cores) and maximum number of tasks running, the CPU Package is cool (~60 degrees Celsius). The fans are silent.
The maximum number of tasks are running, 32 (1 per thread I guess), at the same time. Mostly Rosetta 4.20 and World Community Grid (scienceunited).

However if I change to use fewer cores, like 50% for example, the temperature rises quickly to 85 degrees. Same thing happens if I tell the manager to pause some of the tasks. It gets really hot and loud, very fast.

CPU: AMD Ryzen 9 5950x (16 cores).
No GPU in use.
ID: 105414 · Report as offensive     Reply Quote
Profile Keith Myers
Volunteer tester
Help desk expert
Avatar

Send message
Joined: 17 Nov 16
Posts: 611
United States
Message 105415 - Posted: 15 Sep 2021, 19:50:11 UTC - in response to Message 105414.  

Check your fan profile. Also if using the auto overclock feature of the cpu, then the cpu will boost frequencies and the necessary voltages to achieve those clocks when lightly loaded.
High cpu utilization will lower the clocks and the voltages.
High cpu voltages will produce higher temps.
Either increase the fan profile speeds and lower the ramping threshold or turn off the auto overclock.
ID: 105415 · Report as offensive     Reply Quote
Wartem

Send message
Joined: 12 Sep 21
Posts: 2
United States
Message 105416 - Posted: 15 Sep 2021, 20:21:29 UTC - in response to Message 105415.  
Last modified: 15 Sep 2021, 20:42:06 UTC

Thanks for the reply.

Regarding Auto OC
I have not done any OC and there are no game modes, Precision Boost Overdrive activated or similar.
I'm the first user of it. Maybe the processors are shipped with some kind of auto overclock from the factory.
I will look in to this further.

Regarding fan profile
I will learn more about it.

Example
100% utilization with Boinc: 62 degrees Celsius.
15% utilization with Boinc: 85 degrees Celsius.
Terminate the manager: Quickly down to 50 degrees. Idle at 40 in Windows 10.
15% utilization from apps in the background and playing GTAV: 72 degrees.
ID: 105416 · Report as offensive     Reply Quote
Profile Keith Myers
Volunteer tester
Help desk expert
Avatar

Send message
Joined: 17 Nov 16
Posts: 611
United States
Message 105417 - Posted: 15 Sep 2021, 21:13:48 UTC - in response to Message 105416.  

PBO IS an aggressive overclock. Quite so. You will be seeing cpu voltages approaching and over 1.4V in the processors attempt to maximize clocks for high gaming rates.

None of the stock OC algorithms, like PBO, Performance Boost, or CPPC is amenable to 24/7 90-100% utilization in distributed computing.

Best is turn off all those features and just run a stock fixed clock at a reasonable fixed or offset cpu voltage to keep the temps under control.

The Ryzen 5000 cpus like your 5950X does run much hotter than the previous 3000 series. About a good 10° C. in fact. My 5950X runs around 77-80°C with 93% utilization with good custom water cooling.

I run at 4.425Ghz at 1.26V loaded for those temps.

An air-cooled 5950X will run much hotter even with the best Noctua NH-D14/15 dual tower cooler. Again, try 100% fan speed on your cooling solution.

What you are describing as your issue seems entirely normal to me. Adjust your expectations or make changes to your operating profile.
ID: 105417 · Report as offensive     Reply Quote
ProDigit

Send message
Joined: 8 Nov 19
Posts: 648
United States
Message 105438 - Posted: 17 Sep 2021, 19:09:56 UTC

PBO should be auto enabled.
If you want to run less threads, you can always disable SMT.
That way you'll max out at 16 threads.
PBO you can also configure to run at a limited temp or power profile.
Though sometimes it breaks through either the power or temperature profile without warning.
I've had my CPU run at 90C when it disregarded the 75C max limit.
Since then, I have set the 75C max limit, as well as the TDP to like 65W (for a single 120MM water cooler), or 95W for a dual 100mm.
Twin 120mm should easily handle 105-145W.

More than likely, like mentioned, with a lower thread utilization, those ryzens try to constantly put threads into and out of sleep mode, and boost the voltage of others.
Threadrippers and ryzens are made to run either all cores, all threads, or just a few threads at a time.
They don't perform efficiently between ~25-33% and 85%.
ID: 105438 · Report as offensive     Reply Quote

Message boards : Questions and problems : Cool temperatures when at max work but VERY hot when not.

Copyright © 2021 University of California. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation.