X570 Tomahawk Bios not showing CPU fan speeds

stu55jenk151702d7

New member
Joined
Jan 22, 2021
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I have recently built a new AMD computer using a X570 Tomahawk motherboard. I bought a Noctua NH-U12A cpu coller which comes with 2 fans. I have connected the fans using the splitter that comes with the cooler and connected them to the CPU fan header on the MB but when checking bios it does not register the speed of the fan. Any ideas what i'm doing wrong?
 

eqwebbie_with_PC

Experienced Dummy
Joined
Aug 22, 2020
Messages
515
Hi,
I think the splitter is the reason. Two fans means two fan speeds, but only connected to one fan header - this sounds not workable. Which fan's speed should the board show?
 

Alan J T

GRUMPY OLD FART
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Sep 11, 2020
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2,587
Hi,
I think the splitter is the reason. Two fans means two fan speeds, but only connected to one fan header - this sounds not workable. Which fan's speed should the board show?
Na not the splitter one of the Splittes only has 3 connection not the normal 4, fan speed is only read by one fan not both swap the fan connections on the splitter is not the first time Noctua fans have be reported as failing. to show RPM
 

stu55jenk151702d7

New member
Joined
Jan 22, 2021
Messages
2
Thanks for the replies. The fan splitters have 4 connections, I thought this maybe the problem but wanted to double-check. I take it there's no other fan header I can use for the Cpu cooler.
 

Alan J T

GRUMPY OLD FART
Joined
Sep 11, 2020
Messages
2,587
Thanks for the replies. The fan splitters have 4 connections, I thought this maybe the problem but wanted to double-check. I take it there's no other fan header I can use for the Cpu cooler.
Normally one of the Connections for the Splitter has 3 wires the other has 4 but both are 4 pin sockets is just that one of the sockets only has 3 connections and not the normal 4. to read the speed correctly. If both had 4 connections it would be trying to read the speed of both fans at the same time, the connection to the Motherboard is also 4 pin with 4 wires
 
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