How to control MSI 970 Gaming Mobo 3pin Case fans

Dugan22

Commendable
Dec 13, 2016
3
0
1,510
So I know how to control the fans that are listed for me. System fan 1 & 2, cpu, gpu. I Know how to change the speeds and such on my Bios and command center. BUT it does not show me system fan 3 & 4 which are 3 pin. I looked everywhere to see if they popped up. No where in my bios or command center does it show me system fan 3 & 4. Even checked MSI AFTER BURNER. If anyone knows how to change the speeds of the 3 pin fans please tell me, my hears hurt from how load these 2 fans are haha.
 
Solution
Unfortunately you are looking for something that does not exist.

Your mobo manual says that the SYS_FAN1 and 2 headers use Voltage Control Mode to power and control their fans. Although they have 4 pins, these headers behave only as 3-pin fan headers, but that's OK. That system can deal with both 3-pin and 4-pin fans. (It just cannot be used with 4-pin fan HUBS, although they CAN be used with Splitters.) BUT the SYS_FAN3 and 4 headers have NO control function at all - they only provide a fixed 12 VDC supply to their fans which then always run full speed. That is why BIOS does not have any place to adjust those headers.

The solution is relatively simple. You need to buy two simple Splitters, like this...

Paperdoc

Polypheme
Ambassador
Unfortunately you are looking for something that does not exist.

Your mobo manual says that the SYS_FAN1 and 2 headers use Voltage Control Mode to power and control their fans. Although they have 4 pins, these headers behave only as 3-pin fan headers, but that's OK. That system can deal with both 3-pin and 4-pin fans. (It just cannot be used with 4-pin fan HUBS, although they CAN be used with Splitters.) BUT the SYS_FAN3 and 4 headers have NO control function at all - they only provide a fixed 12 VDC supply to their fans which then always run full speed. That is why BIOS does not have any place to adjust those headers.

The solution is relatively simple. You need to buy two simple Splitters, like this:

http://www.newegg.com/Product/Product.aspx?Item=N82E16812423168&cm_re=cobo_fan_splitter-_-12-423-168-_-Product

(Whether you get 3-pin or 4-pin splitters does not matter - either will work for you.)

Disconnect the two fans from the SYS_FAN3 and 4 headers. Use the splitters to connect two fans to each of the SYS_FAN1 and 2 headers. This will put all of your fans under automatic control. It is quite OK to hook up two normal case ventilation fans to each SYS_FAN header.
 
Solution

Dugan22

Commendable
Dec 13, 2016
3
0
1,510


So if i get the one you linked and put 4 pin connecters on the 3 pin split the mobo will auto control?
Just making sure before i purchase.
 

Paperdoc

Polypheme
Ambassador
Thanks for Best Solution.

I made the assumption that you have 4 case ventilation fans, and that's why you are using 4 headers now. That's why I said get two splitters, each with 2 output arms. That will connect two fans each to the two headers you have that CAN control your 3-pin fans.

The connectors for 3-pin and 4-pin fan systems are all designed to plug into each other; you can easily plug a 3-pin fan (or splitter) into a 3-pin OR a 4-pin header. Likewise, you can plug a 4-pin fan into a 3-pin header. The male headers have a plastic "finger" that sticks up next to the first 3 pins, and the female connector has a groove on the side that matches that, so you can only plug them in one way. The pin layout for the first three pins is the same (with a small distinction), and the 4-pin system merely adds an extra pin for a different function that 3-pin systems don't use.

Net result is that, assuming your SYS_FAN1 and 2 headers are controlling their two fans now, when you use Splitters like I linked, each of those headers will power AND control both of the fans attached to it. You will NOT see the speed of all the fans, though. A fan header can only accept the speed signal from ONE fan, so each splitter only allows ONE of its fans to report its speed to the mobo. The other (2) fans' speeds are simply ignored.

My link was to a simple and cheap splitter design, and you don't need more. There are others with plain wires, some with three outputs, some just more expensive but don't do the job any better. 3-pin or 4-pin does not matter. Just do NOT get a HUB. Some Hubs may look very similar, but their distinguishing feature is that they all have an extra arm that MUST plug into a power output directly from the PSU. Hubs only work in 4-pin fan systems and can't do what you need.