Double fans on Noctua NH-U14S?

[btng]

I have a Threadripper CPU + a Noctua NH-U14S cooler. I have a few questions regarding the setup:

 

1. Is it recommended to run 2 fans on that cooler (one intake and one exhaust)? If so, does it make a big difference? Does the noise go up a lot with 2 fans instead of one?

 

2. I read in the manual that if I would go for the 2 fan option the exhaus should spin slower than the intake fan. How do I achieve this? Can I still do this with 2 NF-A15 HS-PWM or do I need to buy some other type of fan?

 

Thanks a lot!

[jiyeon]

4 minutes ago, btng said:

1. Is it recommended to run 2 fans on that cooler (one intake and one exhaust)? If so, does it make a big difference? Does the noise go up a lot with 2 fans instead of one?

Yeah, that's called a push-pull setup, one fan intakes and the other exhausts, maximum efficiency for heat dissipation since the heatsink is flanked with airflow from both fans. Noise depends on the fans used.

Two fans aren't always needed, however, it's ultimately up to if you want to utilise your cooler to its potential.

[LogicalDrm]

Noise doesn't go up so much that you would notice it. Also spinning speed is irrelevant, just use the included pads to have exhaust side bit more away from heatsink. If your mobo has two CPU fan headers, have fan on each. I have it so 2nd only spins up when CPU temp goes over 60C.

 

On mine max temps did drop by 5-7C.

[btng]

2 minutes ago, LoGiCalDrm said:

Noise doesn't go up so much that you would notice it. Also spinning speed is irrelevant, just use the included pads to have exhaust side bit more away from heatsink. If your mobo has two CPU fan headers, have fan on each. I have it so 2nd only spins up when CPU temp goes over 60C.

  

On mine max temps did drop by 5-7C.

Which one does only spin when temps go over 60C? Exhaust?

[btng]

From the manual:

 

Quote

The y-cable supplied with the retail NF-A15 fan can be used to control the speed of both fans via the same mainboard fan header.

Please note that while the NF-A15 fan included with the NH-U14S TR4-SP3 runs at 1500 rpm, Noctua recommends using the standard 1200rpm retail version as a rear fan in  push/pull mode as the combination of 1500rpm at the frot and 1200rpm at the rear will provide the best balance of performance and acoustics. 

If you would like to run both fans at the same speed, please use the supplied Low-Noise adaptor on the front fan to reduce the speed to 1200rpm. 

3

Which is the "standard retail version" that they talk about here?

[LogicalDrm]

17 minutes ago, btng said:

Which one does only spin when temps go over 60C? Exhaust?

 

I think exhaust, but I'm not sure. I've changed its orientation once after adding fan.

 

13 minutes ago, btng said:

From the manual:

 

Which is the "standard retail version" that they talk about here?

The one you buy separately I think. But you can achieve same with speed controls anyway.