B550M Pro4 High CPU Temps
Printed From: ASRock.com
Category: Technical Support
Forum Name: AMD Motherboards
Forum Description: Question about ASRock AMD motherboards
URL: https://forum.asrock.com/forum_posts.asp?TID=14823
Printed Date: 29 Jun 2025 at 12:02pm
Software Version: Web Wiz Forums 12.04 - http://www.webwizforums.com
Topic: B550M Pro4 High CPU Temps
Posted By: bigbangus
Subject: B550M Pro4 High CPU Temps
Date Posted: 29 Jun 2020 at 9:30pm
|
Asus B550M Pro4 V1.10 running with Ryzen 5 3600 @ stock speed (1.4V core) and DDR4 LPX vengeance 3200 @ 3200MHz I'm getting the BIOS HW menu showing 65degC!!! I removed the stock cooler, cleaned off everything and re-applied Artic MX-4 paste. Visually checked that it covered all edges of CPU from case peep holes and it looked good. All screws tight on wraith cooler. All visuals good. Still BIOS is showing 62+ degC! My ambient is 23degC... Case is Fractal design node 804 with 3 case fans blowing at 700rpm. CPU fan is set to max 1900rpm. When I go into my O/S Unraid using the Dyanmix Temp plugin, the cpu is reporting 39degC.... wtf Is there something wrong with the temperature reported in the BIOS??? ------------- ASRock B550M Pro4 1.1 Ryzen 5 3600 @ stock LPX Vengeance 2x8GB 3200 @ 3200 |
Replies:
Posted By: ThreeDee
Date Posted: 30 Jun 2020 at 1:45pm
|
what are your temps whilst in Windows? ------------- |Ryzen 5 5900|ASRock X570 Taichi-BIOS 4.60|2x16GB HyperX Predator RGB 3200@3600 1:1 IF|ASRock RX 6700XT|2 x PCIe 4.0 M.2 Drives for OS & Games|850 WTT Seasonic 80+ Titanium PSU|Noctua NH-D15| |
Posted By: bigbangus
Date Posted: 30 Jun 2020 at 9:25pm
|
I'm using unraid O/S, but to answer your question I dusted off an old SSD and booted bare metal into Win10. I installed the AMD software and it was showing 40+°C. If I go into the motherboard bios to the temperature / fan control tab, it shows 65°C. This is definitely a bug in the BIOS! ------------- ASRock B550M Pro4 1.1 Ryzen 5 3600 @ stock LPX Vengeance 2x8GB 3200 @ 3200 |
Posted By: Xaltar
Date Posted: 30 Jun 2020 at 10:10pm
|
It isn't a bug, it's because the BIOS utilizes a single core at full frequency and voltage the entire time you are in the UEFI. The size of the BIOS chip means there simply isn't enough space to incorporate power saving of any kind. The end result is a single core runs at near 100% load the entire time and gets hot. If your cooling solution is keeping you under 80c in the BIOS then you are likely not going to have any thermal issues in OS. You are not the only one that was bothered by the high temps in the UEFI  I did a lot of research into it and asked some of my industry contacts about it. The old text based BIOS setup was a lot less demanding and showed temps much closer to what you would expect at idle in OS. It was also a lot less versatile. Also bare in mind that I am talking about AMD in this instance (under 80c), most BIOS temp monitoring monitors the tCTL sensor which is meant to be offset by between -10c and -27c depending on the CPU model (threadripper is -27c). In practice this usually means that if you are seeing 65c on an AMD Ryzen based system you would likely see 55c on an intel board. Feel free to look up tCTL in more detail if you like but in a nutshell, it exists to conrtol (CTL) the fans, by the fan controller thinking that the temps are higher than they are it responds much more rapidly. I suspect this is a limitation of fan controllers that were never designed to manage such rapid heat fluctuation, more cores heating up together means much sharper temp spikes than on older dual and quad core setups that were the norm not that long ago. I imagine new controllers will emerge eventually and the tCTL workaround will be abandoned but I doubt it is a priority as the current method works very well and doesn't cost anything to implement vs designing a new IC. ------------- 
|