[SOLVED] 3900XT Questions regarding heat & more

Nov 27, 2020
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0
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I recently built a PC. This was my first time using Ryzen and an AIO (specs below).

Upon first boot, CPU temps in BIOS were higher than expected. They started at 51 and gradually went to 57-60c. I installed Windows and checked Ryzen Master and then closed it and tried HWinfo. Idle is generally between 50-60c in both apps. Sometimes spiking over 70 opening browser, etc. I ran Cinebench R23 multi-core and it resulted in a temp of 85-87c and 18172 score. I turned off PBO and it still hit 85c in Cinebench with idle around 50c. Coolant temp was 35c during test.

I redid thermal compound because I originally used the preapplied stuff, it did not seem to have a noticeable effect on temps. I also reversed fan directions. The case has high airflow and temp of everything else (including GPU in games) is quite low/average so I don't think this is a case issue.

Room temp is 27c.

I see elsewhere people saying they get much lower temps with this CPU/AIO combo. I don't understand why I can't. Other than potentially replacing the AIO, how do I determine why?

Ryzen 9 3900XT
Corsair H100i RGB Platinum SE
Fractal Meshify C Case
ASUS Crosshair VIII Hero X570 MB
Corsair Vengeance Pro RGB 3200MHz 2x16
EVGA RTX 2070 Super XC Ultra
3x QL120 (2xLL120 on AIO)
Samsung 970 Evo Plus 1TB NVMe m.2
 
Solution
Also, something I noticed is CPU CCD1 will be at like 78c for example, and CCD2 temp will be 61c in HWINFO. Is it normal for there to be such a large discrepancy under load between the two?
Yes. It's the way ryzen works.

Ryzen boosts one single core from sleep to max clock to process a load and then puts it back to sleep. Another load comes along and the scheduler hits another core, maybe on another CCD, to process it. So one CCD might be getting hotter than the other if the scheduler is hitting cores on that CCD more frequently.

Also, when it boosts a tiny area of the cpu will spike in temperature and that's what you're seeing. It's not really significant though. Like a match in a room...match hot, room not. To understand the...
Nov 27, 2020
2
0
10
Also, something I noticed is CPU CCD1 will be at like 78c for example, and CCD2 temp will be 61c in HWINFO. Is it normal for there to be such a large discrepancy under load between the two?
 
Also, something I noticed is CPU CCD1 will be at like 78c for example, and CCD2 temp will be 61c in HWINFO. Is it normal for there to be such a large discrepancy under load between the two?
Yes. It's the way ryzen works.

Ryzen boosts one single core from sleep to max clock to process a load and then puts it back to sleep. Another load comes along and the scheduler hits another core, maybe on another CCD, to process it. So one CCD might be getting hotter than the other if the scheduler is hitting cores on that CCD more frequently.

Also, when it boosts a tiny area of the cpu will spike in temperature and that's what you're seeing. It's not really significant though. Like a match in a room...match hot, room not. To understand the true thermal state look at CPU Die (average) in HWInfo64.
 
Solution

93boba

Distinguished
Nov 24, 2015
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18,715
I recently built a PC. This was my first time using Ryzen and an AIO (specs below).

Upon first boot, CPU temps in BIOS were higher than expected. They started at 51 and gradually went to 57-60c. I installed Windows and checked Ryzen Master and then closed it and tried HWinfo. Idle is generally between 50-60c in both apps. Sometimes spiking over 70 opening browser, etc. I ran Cinebench R23 multi-core and it resulted in a temp of 85-87c and 18172 score. I turned off PBO and it still hit 85c in Cinebench with idle around 50c. Coolant temp was 35c during test.

I redid thermal compound because I originally used the preapplied stuff, it did not seem to have a noticeable effect on temps. I also reversed fan directions. The case has high airflow and temp of everything else (including GPU in games) is quite low/average so I don't think this is a case issue.

Room temp is 27c.

I see elsewhere people saying they get much lower temps with this CPU/AIO combo. I don't understand why I can't. Other than potentially replacing the AIO, how do I determine why?

Ryzen 9 3900XT
Corsair H100i RGB Platinum SE
Fractal Meshify C Case
ASUS Crosshair VIII Hero X570 MB
Corsair Vengeance Pro RGB 3200MHz 2x16
EVGA RTX 2070 Super XC Ultra
3x QL120 (2xLL120 on AIO)
Samsung 970 Evo Plus 1TB NVMe m.2

Update your BIOS to the latest version.
Afterward, change power plan settings "Min CPU" to 20% and Max CPU to 99%. (Update all your drivers - find them on official ASUS)
 
Max CPU at 99% will kill all boost and limit CPU to base frequency. For best performance Ryzen needs temps no higher than 70c and a 340mm AIO is not going to cut it with 12 cores.
You need to cut voltage down to 1.3v or less, try with negative offset 0.005-0.1v.