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CPU_FAN vs W_PUMP for AIO water cooler

nCubed
Level 7
Case: Fractal Define XL R2
CPU Cooler: Fractal Kelvin S24
Motherboard: Asus ROG Maximus VIII Hero
Processor: Intel Core i7-6700K 8M Skylake Quad-Core OC to 4.6 GHz
Memory: 16GB G.SKILL Ripjaws V Series DDR4 SDRAM 3200 (PC4 25600)
Graphics Card: ASUS GeForce GTX 980 Ti STRIX 6GD5
Power Supply: SeaSonic Snow Silent-1050 1050W 80 Plus Platinum

I have connected the Fractal Kelvin S24 radiator fans to the 4-pin CPU_FAN connector and the pump to the 4-pin W_PUMP connector.

My questions:

  • Is there any voltage difference between the CPU_FAN and the W_PUMP connectors? I ask because the Hero VIII manual says the CPU_FAN is 1A / 12W, but does not state the wattage of the W_PUMP; and Fractal recommends leaving the pump at 100% voltage at 12W.
  • Should I have connected the pump to the CPU_FAN instead of the W_PUMP based on the prior question?


This is my first AIO, or any water cooling for that matter, and the pump sounds much louder than the spec'd 32db's; something like a low grinding sound. Is that normal?

FWIW: I had a be quiet! Dark Rock Pro CPU tower which was completely inaudible under every day usage, but could not handle the temps under load when OC'ing to around 4.6, even with 3 case fans and the 2 CPU fans running at 100%. Thus, my attempt at using an AIO.

For reference:
Fractal Kelvin S24 product page:
http://www.fractal-design.com/home/product/water-cooling/s24

Fractal Kelvin S24 manual (scroll down towards bottom of page):
http://www.fractal-design.com/home/downloads
14,630 Views
7 REPLIES 7

Nate152
Moderator
Hello nCubed

The W_PUMP header is the same as the cpu fan header 1amp - 12w.

You can let the kelvin cooler connected to the W_PUMP it says it draws 0.27 amps. A low grinding noise doesn't sound good, you might want to ask fractal tech support about that.

52909

Nate152 wrote:
The W_PUMP header is the same as the cpu fan header 1amp - 12w.

You can let the kelvin cooler connected to the W_PUMP it says it draws 0.27 amps. A low grinding noise doesn't sound good, you might want to ask fractal tech support about that.


Thanks Nate152. I just found this where Fractal (un)officially said the pump can be run at 9w to reduce pump noise if not expanding to cool the GPU (see Fractal's reply about 1/2 way down):
http://hexus.net/tech/reviews/cooling/78029-fractal-design-kelvin-s24/?page=4

Do you know how to set the W_PUMP (or any connector) specifically to 9w? (I have also submitted a support request to Fractal about the excessive noise).

Nate152
Moderator
You should be able to control the pump by voltage control in the bios, you can ask them when they reply to your support ticket.

Nate152 wrote:
You should be able to control the pump by voltage control in the bios, you can ask them when they reply to your support ticket.

I'm pretty sure Fractal support is not going to provide information on how to adjust Asus bios settings 🙂 I was wondering if you (or anyone else) knew how to set a fan with specific wattage? I've gone through the bios (v1001) and can only see a way to switch between PWM and DC mode; I'd expect DC mode to have voltage settings, but I didn't see any. Given that the Kelvin connectors are 3-pin, PWM won't even register, so DC should be used (at least that's what I was thinking).

TLDR; Do you know how to specifically set fan voltage/wattage in the Asus bios?

Praz
Level 13
Hello

Setting connected devices by voltage or wattage would be convoluted at best. The speeds are set by RPM/percentage values. A pump that draws a maximum of 0.27A is not much of a pump. It would be best to run it at full speed at all times.

Praz wrote:
Setting connected devices by voltage or wattage would be convoluted at best. The speeds are set by RPM/percentage values. A pump that draws a maximum of 0.27A is not much of a pump. It would be best to run it at full speed at all times.


I'm making the assumption right now that my pump is defective because it does sound quite loud; a smart-phone app measured it at approx. 60db and it is spec'd at 30db or so. Not that the app is going to be super-accurate, but I'd imagine I'd be somewhat close.

Reducing the voltage will reduce the pump noise.

I should have looked at all the included parts, re: I just found on the product website this listing under package contents: "Low speed cable for pump (9V)"

I'll try the 9V cable and will continue to follow up with the manufacturer about the pump noise.

adrifoxbg
Level 9

Screenshot from 2023-04-06 13-40-34.png

arctic liquid freezer ii 420 rgb

Motherboard ASUS ROG MAXIMUS Z790 HERO
Intel Core i9 13900k processor

actually i am also facing this dilemma right now.

asus recommend for liquid cooling the use of the correct headers aio_pump or w_pump

aio pump is the same as cpu fan with the difference that the cpu fan is still controllable, the two liquid cooling headers run at 100% full speed PWM

w_pump+ is 36W 3A full speed pwm

All others are 1A 12w and only aio_pump is at full speed

According to asus, the use of cpu fan header is not recommended, but realistically, if it is not w_pump, everything else is the same in terms of amps and voltage, even aio_pump is not controllable
It's really confusing what is the right thing to use.

Artic recommend using a cpu fan header because long term use at full speed pwm is not good for the pump
And what are we doing ?