New build custom waterloop, fans, pump, PWM fan hub questions (stressing lol)

[spastic-nutcase]

Hi All,
I'm building a PC with a custom waterloop at the moment, and need some suggestions regarding fans & pump using PWM
I'll start with the parts relating to my issue.

MSI z170 gaming M7 motherboard,
NZXT Noctis 450 with PWM fan hub.
Case comes with 3 fans in front, (removed 2, replaced with rad and 2 fans)
2 radiators, one in front one on top each with 2, 4 pin fans.
EK-XRES 140 DDC 3.2 PWM Elite Pump/Reservoir Combo

My issue is that the PWM hub only has 3 pin connections.
My motherboard has 5, 4 pin fan headers, and the speed can be changed in the bios for all 5.

If i plug the 4, 4pin fans into the 3 pin headers on the PWM hub (which connects to the cpu_fan on mobo) then they will run in voltage control mode (im assuimng 100%?) They're 3000rpm fans (EK Furious Vardar Fan F5 120mm) so if theyre running at 100% the whole time that will be really noisy.
And then theres the pump, the connector is a 4pin connector however theres only 2 wires coming out of it, and its supposedly PWM? Thats another thing i dont want running 100%, if that blows it will be a disaster.

Everything was going so well with the build this whole fan situation is confusing the hell out of me =(. To make matters worse the top fans dont even reach the PWM hub.

I dont know if i should just get a fan controller like the NZXT Grid+ V2 and a cable extensions?

Sorry for the long post. Any advice would be really appreciated

 

[rubix_1011]

I think you're over-thinking the PWM on the pump issue. Many people that watercool never use the PWM feature on pumps (including myself). Running it at 100% is perfectly fine and you'll find that it's barely even audible when running...it also isn't going to catastrophically fail, either.

Most people in this situation use a fan controller rather than relying on PWM for that many radiator fans. You can buy some that are expensive bay controllers with LCD or digital read outs or you can find some that are nothing more than a resistor dial.

However, I do see what your idea is and it is a decent one - having one PWM header to control all of your fans so they are getting the same RPM sensor feed. Try Amazon or Ebay for fan extension cables, they should be pretty cheap.

 

[spastic-nutcase]

Thanks heaps for your reply

I have an idea that might work,

The PWM hub needs to go to CPUFAN header to work properly, and it has 1 4pin plug for a cpu cooler.
Idea:

PWM hub --> CPUFAN1 (mobo)
Pump --> 4pin cpu cooler port on PWM hub
2, 3 pin case fans --> PWM hub
2 rad fans --> Y splitter --> CPUFAN2 header
2 rad fans --> Y splitter --> System fan header
that way i dont even need to buy a controller or extensions?

Do you know if the PWM function scales to temps? or if its usually a set speed?

 

[rubix_1011]

PWM typically is a BIOS range scale that ramps fan speed based on reported CPU die temperatures. This is typically a percentage voltage increase or decrease based on thermal load as you don't necessarily know the RPM that would be supported by the fan that is connected.

 

[spastic-nutcase]

Ok cool, i think im just going to go with that and see how i go thanks for the help