Noob question about max current on motherbored fan power connector

[Maximilian17]

Hi.

I'm looking at my motherboard manual and it says that "max current" on CPU_FAN1 is 2A.

If my CPU cooler has 0.08A (arctic freezer 34 CO) and a 140mm case fan current is 0.12A, does it mean that I can safely use a case fan and a CPU cooler fan on CPU_FAN1 power connector? (0.12 A + 0.08 A = 0.2A). My initial assumption was CPU_FAN is a fan only for CPU.

I'm planning to put 3 intake fan and 2 exhaust fan:
-Top exhaust fan is using SYS_FAN1
-Rear exhaust fan is using SYS_FAN2
-Top-front intake fan will be on CPU_FAN1 (along with CPU cooler fan)
-middle-front and bottom-front fans using PUMP_FAN1

My mother board is B560 mortar wifi.

Thank you for your help!

[Razorfish]

The mother board has multiple fan connections.
sometimes the connection is pwm other times DC
if it is PWM then you cannot have multiple items and expect it to work correctly.


Generally the "rating" in this case, it based on the switching transistor & PCB track layout

now if it is a "reputable" motherboard they have a safety margin...
if it is a Chinese motherboard derate by 0.8 because they always lie, since they are in competition and have to clear the stock. (ur on MSI, it's a solid brand from Taiwan)

now "cpu_fan" might actually be a pump or a fan.

Generally you should not mix multiple items unless it is a "special" cooler unit or the manufacturer has special instructions.

Iv'e seen crap from china where they mix a DC fan with a PWM cooler, they don't care , they just sell anything.

have a look at this to understand "PWM"
https://www.ekwb.com/blog/what-is-pwm-and-how-does-it-work/

[PopinFRESH]

Ursprünglich geschrieben von Razorfish:

The mother board has multiple fan connections.
sometimes the connection is pwm other times DC
if it is PWM then you cannot have multiple items and expect it to work correctly.

Care to explain how this works then?

https://noctua.at/en/na-syc1

Ursprünglich geschrieben von Noctua:

The NA-SYC1 is a fan accessory set consisting of two fully sleeved NA-YC1 Y-Cables for 4-pin PWM fans. The NA-YC1 Y-Cables make it possible to run two 4-pin PWM fans on a single fan header and to let the mainboard control the speed of both fans simultaneously. Multiple NA-YC1 can be daisy-chained to control more than two PWM fans via one header

Multiple PWM fans on a single 4pin PWM fan header with a PWM Y splitter will work perfectly fine. The fans will all just load at the same duty cycle.

[_I_]

if using a splitter, the sense/rpm will only detect one fan, not all of them

[Maximilian17]

Ursprünglich geschrieben von Razorfish:

Generally you should not mix multiple items unless it is a "special" cooler unit or the manufacturer has special instructions.

I'm waiting for arctic Cooling P12 PWM PST x 5 Fans. And l just found out that they can be daisy chain together. So I'll use three of these fans into PUMP_FAN1 without using any splitter.

[Bad 💀 Motha]

As long as you don't exceed approx 1.5 amps per fan header you should be fine. On most motherboard it's usually only the water pump fan header that might support higher