AMD Motherboards - Yet another UEFI bug with AB350/X370 ITX/ac

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Yet another UEFI bug with AB350/X370 ITX/ac

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=8166
Printed Date: 10 Feb 2025 at 7:42am
Software Version: Web Wiz Forums 12.04 - http://www.webwizforums.com

Topic: Yet another UEFI bug with AB350/X370 ITX/ac

Posted By: cristy6100
Subject: Yet another UEFI bug with AB350/X370 ITX/ac
Date Posted: 23 Mar 2018 at 10:00pm

This time its a fan header bug regarding Chassis Fan 1/Water pump header, it will not output the full fan voltage so the fan or water pump RPM will be much lower than it should when the header is set to Full Speed, to test this I used 2 Fans and one AIO water pump, for comparison I used the Chassis Fan 2 and CPU Fan 1 header.

The results are as follows:

Fractal Design 140mm 1000RPM fan:

CPU Fan Header 1: 1020-1070 RPM

Chassis Fan 2 : 990-1030 RPM

Chassis Fan 1 : 640-670 RPM

Fractal Design 120mm 1200RPM fan:

CPU Fan Header 1: 1150-1270 RPM

Chassis Fan 2 : 1130-1180 RPM

Chassis Fan 1 : 890-930 RPM

Cooler Master ML120L RGB water pump:

CPU Fan Header 1: 2350-2410 RPM

Chassis Fan 2 : 2310-2350 RPM

Chassis Fan 1 : 1640-1690 RPM

As you can see we can accept a +/- 50-100RPM per header difference because of trace line resistance/length but a full 700RPM drop is very big and its a bug that need to be addressed.

This is not a RPM readout bug, the fans/water pump are spinning slower in realtime.

The bug also occurs if header set to Custom/Silent/Normal/Performance modes, the RPM drop is across the board

Please check and confirm this bug

EDIT1: I will check with a multimeter the pin and report the voltage, but I will need to dissasemble my PC and I really dont have the time right now, tomorrow I will do it, until then if you guys can check with your fans and report back the RPM values, just swap between the fan headers and check RPM in UEFI, no need to reboot between checkups

EDIT2: Both my AB350 and X370 exhibit this bug, both with latest 4.51 bios

Replies:

Posted By: cristy6100
Date Posted: 24 Mar 2018 at 7:10am

Bumped, so people see and read the post, cause I see it as a critical bug loosing 600-700RPM on a fan header... I never ever encountered something like this.... and its a big as it gets bug when you have only 2 Chassis Fan headers and the one with the water pump is loosing 700RPM across the board...

Posted By: wardog
Date Posted: 24 Mar 2018 at 8:11am

Cristy, This is mostly a Community Forum.

Would you be so kind as to report your finding at https://event.asrock.com/tsd.asp" rel="nofollow - https://event.asrock.com/tsd.asp

Fill in and include the system hardware, BIOS rev., fan make and model #'s, etc so that they can look into it. The more detail you include the better obviously.

Thanks in advance,
wardog

Posted By: cristy6100
Date Posted: 24 Mar 2018 at 5:56pm

Thanks for the info, I have reported all found bugs in a good manner in the support mail I have sent

Posted By: cristy6100
Date Posted: 30 Mar 2018 at 12:40am

Bug confirmed when switching the Chassis Fan 1 Control Mode from PWM Mode to DC Mode.

Even if connected Fan is 3PIN DC Control, or a Water Pump, the RPM drop will depend of the Connected FAN/PUMP speed, on a high power Delta 3700RPM fan the RPM drop will be 1300-1400RPM when Control Mode is set to DC Mode and Full Speed, only fix is keeping the control mode to PWM even with 3 Pin fans and water pumps.

I already reported the BUG to ASRock support so a fix will be on the way hopefully...

Posted By: Security Code
Date Posted: 30 Mar 2018 at 12:29pm

I've noted this too with my Be Quiet! 120mm Silent Loop pump attached to Chassis Fan 1.

The pump has a rated speed of 2200RPM and it runs at just under 1700RPM with Chassis Fan 1 set to DC control pump @ max speed (I set it to custom speed and moved all markers to 100% and it ran at 1100RPM).

Also of note, I have had the pump speed drop to around 500RPM making quite a loud unpleasant noise on about four occasions so far, sometimes at boot sometimes when the PC had been running for a few hours. After shutting down completely and then switching back on multiple times it finally returned to proper speed.

Posted By: cristy6100
Date Posted: 30 Mar 2018 at 2:06pm

Yes, for the moment switch to PWM control mode even if you are using 3pin Fan/Pump, if using pump set it to PWM Control and Full Speed it will work with 99% no problems until they fix this