CPU temp. difference between fan headers

[Fryer]

Ok so I just was cleaning my system and getting it ready to sell by doing all the cable management and stuff so I moved my fans around and changed them between the headers. I have a phantom 240 case and in the back I have an exhaust fan then a radiator then another fan so it is a push/pull setup. So I had the case fan plugged into CHA_FAN2 and the radiator fan that is on the other side of the radiator plugged into CHA_FAN1 and my CPU temps were 70c at idle. But then i switched the fans on the motherboard and now the CPU temp is at 40c. I had both fans set to full power before and after I switched them in the bios so i have no idea whats causing this.

 

Specs:

i7-4790

Asus Z97-k

Asetek liquid cooler

Windows 10

Latest bios firmware

[Windows7ge]

Something I learned about motherboards is they commonly have a current/voltage limitation on the fan ports. It's possible your motherboard has at least two separate power sources feeding these headers and the different power requirements for the fans exceeded the respective supply pulling it low. Switching them back put whichever higher power demanding fan on a supply that could give it what it wanted instead of pulling it down due to other system demands. That's only a guess as to the cause though.

 

Honestly a dedicated controller is typically the most reliable. Most do require manual control but you won't have issues like this and you usually get more performance from the fans. If your cooling is efficient enough you can sometimes find a noise:cooling ratio where you don't need to play with the controller at all after initially setting it up.

[Fryer]

2 minutes ago, Windows7ge said:

Something I learned about motherboards is they commonly have a current/voltage limitation on the fan ports. It's possible your motherboard has at least two separate power sources feeding these headers and the different power requirements for the fans exceeded the respective supply pulling it low. Switching them back put whichever higher power demanding fan on a supply that could give it what it wanted instead of pulling it down due to other system demands. That's only a guess as to the cause though.

 

Honestly a dedicated controller is typically the most reliable. Most do require manual control but you won't have issues like this and you usually get more performance from the fans. If your cooling is efficient enough you can sometimes find a noise:cooling ratio where you don't need to play with the controller at all after initially setting it up.

Alright thanks I'll look into one

[Windows7ge]

37 minutes ago, Fryer said:

Alright thanks I'll look into one

Actually now that I think about it does the pump plug into the motherboard? If this gets less power due to any reason you'll see horrific spikes in temps. I'd get an adapter and plug it into a molex or SATA pwr. It'll get a full 12V 100% of the time. Them plug the fans into the two corresponding CPU_FAN1/2 headers. See how it likes that.

[Fryer]

13 hours ago, Windows7ge said:

Actually now that I think about it does the pump plug into the motherboard? If this gets less power due to any reason you'll see horrific spikes in temps. I'd get an adapter and plug it into a molex or SATA pwr. It'll get a full 12V 100% of the time. Them plug the fans into the two corresponding CPU_FAN1/2 headers. See how it likes that.

Yes, it plugs into the CPU_FAN header and that is a great idea I'll try that thanks!