Fan header and fan control

[samisavick]

i have the gaming 3 and i realized that the fan control wont let me go below 50% on case fans so i was wondering  if i can Y cable my cooler master jetflo 120mms as at 50% they run at 1400 rpm which isnt even 50%. but if plugged in a cpu header i can reduce it to 600 rpm. (can system fans get this support)

but ive heard these fans are very power hungry so i was wondering what the max a cpu fan header can support

 

[JLio01]

Do you use command center or set it under BIOS?
The speed of this fan is 800-2000 rpm, so 50% is 1400 rpm, one fan header provide 12V and you use a Y cable so that each fans get 6V, basically it's 50% with voltage control, no difference I think...
You can try put the system fan on other CPU fan connector.

 

[samisavick]

yes i did try connecting to a cpu fan header, im able to get rpm to go below 50% into a minimum of 12.% again why is this not the case with system fan headers.

so what i want to know is what is the maximum amps per fan header as the cm jetflo 120 require 0.4 amps and therefore two off one header would make 0.8 amps, is this an unsafe amount?

 

[Nichrome]

It shouldn't be a problem to use 2 fans on a single header. I use such a splitter and never had issues. Once I had 2 Delta fans (can't remember models etc) but according to the spec, even single of these on a fan header was already out of fan header's specification (Amps)  But nothing broke, though I suggest to not use such powerful ones

Now the % stuff:

CPUFan headers can go down to 25% (or even 12.5%) IF the fans connected to such headers are 4 pinned (PWM). If they're 3 pin and connected to CPUFan header, they will run 100% without possibility to control it.

SystemFan headers are between 50% and 100% no matter if you use 3 or 4 pin fans. Though 3 pinned can be controlled compared to CPUFan header.

 

[JLio01]

One fan header is capable of 1 amps safely. 2 jetflo 0.8 amps would be no problem, but there's no use with Y cable for fan control since the voltage will not change, if you set it as 100% then both fans will get 12V, 50% both fans get 6V(sorry I explained wrong in my previous post), and that's the spec for system fan header to adjust with lowest 50%.