P67A UD4 B3 Fan Headers

[demonsparda]

i only have 3 pin fans and i really wanted to control the fan speed by using voltage regulation instead of PWM (pulse width modulation). so i would like to know which fan headers of this board supports that?

[Lsdmeasap]

It will show you in your manual, the ones that say 12V speed control, and those headers will be able to be controlled via PWM or Voltage.

I can't download your manual to check for you right now, but if you need me to later I can, let me know.

[demonsparda]

thanks for the reply :) i did check the manual, only cpu fan and system fan2 has voltage control..

[Lsdmeasap]

Sounds about normal for most boards. System fan 2 is often half speed, so keep that in mind while deciding where to connect fans.

[demonsparda]

how i wish fan headers were like my abit ip35 pro wherein i can control all 6 fan headers using voltage regulation. by any chance, do you know the max amperage the CPU fan header can support Lsdmeasap? ive read somewhere in this forum that giga x58 supports a max of 2amps, dunno with P67.

[Lsdmeasap]

3amps per header @ 12v, for all Gigabyte boards as far as I know.

[demonsparda]

wow. good to hear. so connecting 2 fans rated .30amps each on the CPU fan header using a 3pin Y splitter should be fine right? is it true that fans require twice their rated amperage to start? sorry for lots of questions hehe

[Lsdmeasap]

Ya, that would be fine even if they only supported 1amp per header.

I've never heard that at all about fan startup, so it's probably untrue

[demonsparda]

Sounds about normal for most boards. System fan 2 is often half speed, so keep that in mind while deciding where to connect fans.

thanks for the info :) regarding the qouted statement, does it mean that any fan connected to system fan 2 will run 50% of its maximum speed without changing anything inside the bios or do i have to set it? and from your experience, can i control the fan connected to sys_fan2 based on cpu temp or motherboard temp?

[profJim]

Some have reported that the "normal" sys_fan2 output voltage is about 5 volts. Some fans don't under-volt well and if connected to this header, they might not even start rotating when your system is powered on. Better quality fans shouldn't have this problem. You will probably find that fans connected to the sys_fan2 header won't vary their speed nearly as much as the cpu_fan and that the fan rpm is consistently in the 45 - 55 % range. With a 4-pin PWM connected to the sys_fan2 header I've found that the system automatically varies the fan speed, but the speed varies very little.

My preference is to use a multi-channel manual fan controller to control the cooling and fan noise in my systems, and have not had any problems or issues when using the Y-splitter fan cables.