4 fans and only 2 motherboard headers.

[doyll]

the problem with the cables is a lot of motherboard even thought they say PWM control just use DC control.

Indeed not PWM control. Many motherboards with 3-pin control on 4-pin headers claiming to be PWM are not really DC control, but pulsed power (PWM power vs PWM control) to fan. So manufacturer claiming PWM are not using PWM control signal on pin-4 to control PWM fans but are instead using PWM power on pin-2 to control fan speed. The headers are powered by PWM power instead of being PWM signal controlled.

should the first question here not be what fins dose he have and what amp's will they pull from the header, then we should see what the header can supple.
lets be clear a fan header as a single fan connection for a reason, they have a max power output and some fans will blow fan headers if you put more than one on it.

Yes, how much power each fan is rated for times 3 or 4 is the approximate power fan draws when starting up or if something is stopping fan from spinning. This is the reason most fan header failures when powering several fans is when system powers on.

Honestly most fans have power ratings more than low enough to allow 2 or 3 fans to be powered by a single fan header, but there are several that draw too much current to be used with a normal splitter.