My case fan is running at full speed

[pcloverakagameboss]

My generic exhaust fan is running at full speed because I put it in PUMP_FAN1 header & I don't have time to get y splitter. I found a program to change my fan Speed should I change the speed using the program or leave it at full speed

Mobo:msi z270 gaming pro carbon

Fan is generic cheap 140mm case fan from ebay

 

[scout_03]

this board has 4 fans connector with the cpu and pump how many fans you have in the case .

 

[pcloverakagameboss]

2 on top 1 in front 1 on side and the generic fan in back

 

[scout_03]

unplug the side one and use this connector for the back until you could get a splitter for the top fans are they any of those that have 4 pins connector .

 

[pcloverakagameboss]

The thing is the side fan is a giant 230mm exhaust fan and the one at the back of my case is 140mm

 

[scout_03]

230 mm low cfm so get the back one on the board and use psu connector for the side fan or pump one if it is a 4 pins so it will be pwm . and recheck temp .

 

[raisonjohn]

Your fan is running full speed since it is highly likely a 3-pin (DC) fan plugged in a 4-pin header in PWM-mode. Such scenario will provide constant (full) +12V on the fan and makes it run 100% (noisy).

Your motherboard has 6 total fan headers (CPU_FAN1, PUMP_FAN1, SYS_FAN1, SYS_FAN2, SYS_FAN3, and SYS_FAN4). All are 4-pin headers but have the capability to be set either in PWM-mode or DC-mode.

By default, both CPU_FAN1 and PUMP_FAN1 headers are set in PWM-mode, while all 4 SYS_FAN headers are set in DC-mode.

This is the reason why your other four 3-pin case fans (which are plugged in the SYS_FAN1-4 headers) are not running in full speed because, by default, they are set in DC-mode (changes speed due to variable voltage).

However, your generic rear exhaust fan, which is most likely another 3-pin fan, should be run in DC mode like the other SYS_FAN headers. Plugging it on the PUMP_FAN1 in default PWM-mode will run it full speed.

So, simply just set the mode for the PUMP_FAN1 header from PWM to DC and you should be all set:

Access BIOS (press DEL on boot). Click HARDWARE MONITOR. Click PUMP 1. Set the mode to DC. Adjust Fan Curve (Smart Fan Mode) if you wish to set custom points at which the fan connected to the PUMP 1 header will at specific speeds at a given temperature.