It usually works to connect two fans to one header with a splitter cable.
Connect two fans to one header.
When all fans are the same model.
I have a 420 rad in push pull and my logic went like this.
Use 83 of header rating to account for inrush current 1500 rpm fans.
I had several fans from older computer builds so i hooked up 6 of them together all red bunched and all black bunched to make a bigger fan that i will us.
Basically the block you attach to the cpu has a pump installed this pump head is powered by connecting the sata capable and there s also what looks like a 3 pin female that appears to connect to a fan header the pump is also connected to your motherboard by an internal usb connection the pump head also has two places where you can.
But make sure that fan controller can support the needed ampere to run all fans.
Each fan header is rated for up to 1 amp.
Do not connect all 3 yellow to one input.
Some high end boards will have one or mor 2a headers.
So again using that typical 140mm 1250 rpm fan 0 14 amps.
What ever you do.
Gelid solutions pwm y cable connect two pwm fans to one socket the pwm signal input from the mainboard is used to control a series of connected pwm fans for optimal performance in noise and cooling.
There is only one caveat.
Otherwise it can damage the fan controller.
That s true for either dc fans or pwm.
1250 rpm fans.
If the total current drawn by the two fans is less than that rating they can share the header but not if the total current exceeds 1 amp.
Use 75 of header rating to account for inrush current.