Looking for advice on case fan configuration and connections to the motherboard

[Curadusk]

Hi All,

 

1. I'm trying to connect 4-6 PWM fans to my motherboard, but not sure how it should be done correctly. There are enough connectors on the motherboard, but I don't know if the fans break if I connect them to W_PUMP+ or H_AMP as those seem to have higher max current and power than the rest of the fans.

2. My CPU cooler came with a splitter, which is labelled as a Noctua Y-Cable NA-YC1. Can this be also used to split any fans? Interestingly the cable is splits into two PWM connectors, but one of them is missing the 3rd pin (FAN IN). Does this mean, that both fans would report as one fan and one of the fan RPMs would be ignored?

3. I'm planning to get some Noctua fans, but I'm not sure how many. I need to cool an RTX 3080 and a Ryzen 9 5900X. For the front I can either connect 3x120mm fans or 2x140mm fans. If I take 2x140mm fans, how do I need to position them? Does the PSU need any airflow? For the top I can connect 0-2x140mm fans. For the back just one 140mm fan, but I'm not sure if it needs to be a higher RPM or just a normal one is enough.

 

I would like to avoid using fan controllers, since I don't plan to connect that many fans and I just want the BIOS to control the fans. I think this is not possible with fan controllers.

 

I'd appreciate any advice. Thanks.

[Chris Pratt]

The CPU fan header should obviously be reserved for the fan(s) on the cooler, if you're air cooling. Don't daisy chain any other case fans. The Y splitter Noctua supplies is for connecting the two fans on their dual-fan tower coolers, so they both can go into the same CPU fan header.

 

PUMP headers should only be used with AIOs or other liquid cooling. Leave them alone if you're not doing that. The case fans should plug into the ones labeled CHA_FAN, which stands for chassis fan. If you need to, you can usually daisy chain 2-3 fans on the same header, depending on the fan voltage. If you need more than that, that's when you would get a hub.

 

As for orientation, it's impossible to tell you the best layout without knowing what case you have. Generally speaking, you should not fall into the trap of trying to fill every spot for a fan, as more fans doesn't equal more better. You are ideally looking to create neutral pressure in the case (roughly equal intake and exhaust) and a smooth straight path from intake to exhaust, that washes over your components in between. Be mindful of doing things like putting an exhaust fan right next to an intake, as you'd basically just be immediately throwing out the fresh air.

 

Also, consider the overall airflow of the case. If you've got a solid front (not mesh), you should get high static pressure fans for the front intake, as they'll need it to help pull fresh air from the side vents or whatever. Same applies if there's any obstructions like a drive cage in between the fans and you other components.

[narrdarr]

1 it doesn't matter. 

2. the 3rd pin is missing on the splitter because the motherboard only needs to talk to 1 fan,but both fan will run at the same speed. 

3. what case and cooler are you using?

[Mark Kaine]

48 minutes ago, Curadusk said:

Can this be also used to split any fans? Interestingly the cable is splits into two PWM connectors, but one of them is missing the 3rd pin (FAN IN). Does this mean, that both fans would report as one fan and one of the fan RPMs would be ignored?

Yeap, I have 3 noctua y splitters in my case,  2 of them for case fans (2x2) and interestingly 2 of them are bequiet silent wings 2 DC and I can control them just fine, at least on one motherboard header the other seems to only support pwm,  i also can't control the DC fans with the cpu header,  it's pwm only again it would seem .

 

So while there really isn't a guarantee,  it should work especially if you have pwm fans,  dc is more finicky in my experience. 

 

And yes, the 2 fans connected to the splitter will always be seen as one by the motherboard. 

[Curadusk]

My case is a Fractal Define R6. My CPU cooler is a Noctua NH-D15 SE-AM4. Both the front and the top of the case have filters on them. The front door of the case can be opened. Does it make sense to maybe put a fan on the bottom of the case?

 

Regarding the front case fans, which combination and positioning you think is best?

[Curadusk]

On 4/4/2021 at 5:07 PM, Chris Pratt said:

As for orientation, it's impossible to tell you the best layout without knowing what case you have. Generally speaking, you should not fall into the trap of trying to fill every spot for a fan, as more fans doesn't equal more better. You are ideally looking to create neutral pressure in the case (roughly equal intake and exhaust) and a smooth straight path from intake to exhaust, that washes over your components in between. Be mindful of doing things like putting an exhaust fan right next to an intake, as you'd basically just be immediately throwing out the fresh air.

 

Also, consider the overall airflow of the case. If you've got a solid front (not mesh), you should get high static pressure fans for the front intake, as they'll need it to help pull fresh air from the side vents or whatever. Same applies if there's any obstructions like a drive cage in between the fans and you other components.

My case is a Fractal Define R6. My CPU cooler is a Noctua NH-D15 SE-AM4. Both the front and the top of the case have filters on them. The front door of the case can be opened. I've removed all the drive cages, so they don't impede airflow. Do you have any recommendations for this combination.

[Curadusk]

On 4/4/2021 at 5:08 PM, narrdarr said:

3. what case and cooler are you using?

My case is a Fractal Define R6. My CPU cooler is a Noctua NH-D15 SE-AM4. Both the front and the top of the case have filters on them. The front door of the case can be opened.