How many fans on a single mother board connector

[Shrek]

I have 3 input 120mm fans on my case that are powered directly off the power supply, but I am thinking to replace them with fans that run off the motherboard; what are the current limitations of a single 4 pin header?

 

[Ruru]

Your motherboard's manual doesn't specify the max power of the fan connectors, so I guess that they're 1A/12W each. Just don't go over that.

 

[dirtyferret]

typical fan header is 1a but check your mobo specs

 

[Shrek]

B460M DS3H AC Y1 manual does not seem to specify the current limit.

 

[silentbogo]

It depends on the PWM driver IC, but assuming each port has a dedicated IC, they are usually rated to at least 500mA continuous(cheap Nuvoton 3941S and similar). So, while one header may be enough "in theory" for three typical 120mm fans, I'd split it between two headers just in case. Or if you get some quiet fans with 50mA rating - then you can throw everything onto a single header via splitter and forget about it.

Basically check the fans you are planning to get, add up a total max current, and if it's less than 0.5A - just go for it. I have 3 fans on a single connector in my office rig, and it's been fine so far. Though, the fan control IC is rated for up to 1A continuous.

 

[dirtyferret]

B460M DS3H AC Y1 manual does not seem to specify the current limit.

check the BIOS settings, it may tell you there

I have 3 fans on a single connector in my office rig, and it's been fine so far. Though, the fan control IC is rated for up to 1A continuous.

most likely .2 & .3 fans so 1a would be more than enough especially if they are not full speed