I have a very good coolers fans and heatsink, the CPU-Temp is very low like 24C when idle but the minimum Fan Speed at 20% PWM is about 1700RPM.
That is why I would like to setup my CPU-Fan to 0% or to 5% and Chassis FAN to 5% or 10% with manual Q-fan profile when idle.
I need mod two BIOS version which I used to use.
According to my test there is (20%/31% and 30%/20%) limitation in this two version of ASUS BIOS:
Bios version 2702: CPU fan low limit 20% and chassis fan low limit 31%.
Bios version 3503: CPU fan low limit 30% and chassis fan low limit 20%.
I have no experience with moding BIOS so could anybody help me please.

Thanks in advance.

https://www.asus.com/us/Motherboards/SAB.../HelpDesk_BIOS/

@palocr - All other fans, except CPU, have a hidden "allow fan stop" setting, which is applied once temp at those fans sensor is below the set low temp limit. I can make those visible for you and I think that would resolve all your issues for fans other than CPU, unless you don't want them stopped totally?
As for actually changing the Min Duty Cycle limit for CPU and others, I've tried in the past and user said it didn't work, but I can't remember if I changed all possible locations (I assume I did, but you know how assuming goes )

Before I do anything, please F12 some screenshot of your entire "Monitor" BIOS page at that root level, scroll up/down as needed, so I can see what you see vs what is hidden.
Put all images into a zip or rar and upload for me. Then I will make all "Allow Fan Stop" visible for you and any other hidden settings there, and we'll do a single test of changing CPU Min Duty Cycle to 5% if that's OK with you?

Hello, thank you for reply, (I was out for almost month). Pls. I do not want to stop FAN completely (disconnect Fan will solve this). I would like to remove lower limits on "CPU Fan Min. Duty Cycle (%)" and "Chassis Fan 1 Min. Duty Cycle (%)" to 5% or 10%. Thank you in advance. P.