AIO Pump and CPU_FAN

[AYDANN6ix9ine]

So let's say you have a 120mm Corsair H55 Liquid Cooler. Do you connect the Corsair fan to the CPU_FAN header and the water pump into the Water Pump header on the motherboard?

[LukeNukem9]

I think you plug the pump into the CPU cooler but i may be wrong. I always thought the pump header would be for a standalone pump in a custom watercooling setup.

[WoodenMarker]

Yea, that works. They're both just fan headers with convenient labels.

[Enderman]

9 minutes ago, WoodenMarker said:

Yea, that works. They're both just fan headers with convenient labels.

No, pump headers deliver full 12V while CPU fan headers are controlled by temperature and a fan curve.

 

For AIOs that do not have separate molex/sata power they should be plugged into a pump header, not fan header.

Unless you have the option in uefi to disable the fan header so that it delivers full voltage, which you can do on some asus boards.

[Jay Deah]

whilst enderman means well with his response. for this specific cooler its not correct

 

you COULD plug the pump and fans in seperately, but don't... the AIO takes care of it all for you, just connect the single connector to CPU_FAN and let everything else run off of the corsair built in hub stuff.

[WoodenMarker]

37 minutes ago, Enderman said:

No, pump headers deliver full 12V while CPU fan headers are controlled by temperature and a fan curve.

For AIOs that do not have separate molex/sata power they should be plugged into a pump header, not fan header.

Unless you have the option in uefi to disable the fan header so that it delivers full voltage, which you can do on some asus boards.

There are plenty of cases where pump headers are effectively the same as other fan headers besides the default setting being full speed instead of a default or silent fan curve preset. Many Asus boards for example, support pwm / dc control on their pump headers -- the latter would definitely require less than 12v. 

 

As long as the pump is running and temps are good, lower voltage should be fine. It's safer to not lower the voltage so much that there's risk of the pump stopping or failing to start though. 

 

[Sfekke]

If you hear weird noises from your pump check your BIOS as @Enderman mentioned.

There is usually a setting to change a fan header to "AIO PUMP" or similar.

 

A pump that is running on at the wrong speed is something noticeable.

It'll sound rough and sound like it's trying to take off but failing, if you hear that don't let it do that for too long; change the settings or switch headers.

TL;DR
It'll work, plug it in.
If it sounds broken or something, check the BIOS.
I had that same issue and for short periods it's fine, just fix it asap.

[Enderman]

2 hours ago, WoodenMarker said:

There are plenty of cases where pump headers are effectively the same as other fan headers besides the default setting being full speed instead of a default or silent fan curve preset. Many Asus boards for example, support pwm / dc control on their pump headers -- the latter would definitely require less than 12v. 

 

As long as the pump is running and temps are good, lower voltage should be fine. It's safer to not lower the voltage so much that there's risk of the pump stopping or failing to start though. 

 

The H55 does NOT have a variable speed pump.

It should be receiving 12v at all times or it will get damaged over time or stall.

 

If OP has a motherboard capable of disabling variable speed on his fan headers then sure, but if you just plug it into the pump header you don't need to worry about that.

[Velcade]

Read the manual...

 

 

It doesn't matter.  Plug it into the CPU_FAN for ease of use.

[For Science!]

As long as the user is capable of removing the fan curve (i.e. set it to full speed to achieve a constant 12 V) or force PWM mode (also constant 12 V), I tend to recommend using the CPU_FAN header since if the pump were to fail, this would produce a CPU_FAN error and prevent the system from booting.

[WoodenMarker]

5 hours ago, Enderman said:

The H55 does NOT have a variable speed pump.

It should be receiving 12v at all times or it will get damaged over time or stall.

If OP has a motherboard capable of disabling variable speed on his fan headers then sure, but if you just plug it into the pump header you don't need to worry about that.

Yes, it's good practice to run the pump at 12v and undervolting it isn't recommended by Corsair. That being said, they've also said that people have ran these pumps at ~9-10v with minimal performance issues and there's a big drop in noise when going from 12v to 9v. 

[Enderman]

21 minutes ago, WoodenMarker said:

Yes, it's good practice to run the pump at 12v and undervolting it isn't recommended by Corsair. That being said, they've also said that people have ran these pumps at ~9-10v with minimal performance issues and there's a big drop in noise when going from 12v to 9v. 

1) Maybe on the newer corsair coolers, not on the H55.

 

2) The flow rate of those pumps is already extremely low. Slowing it even more is a bad idea. I highly doubt anyone who claims "minimal performance issues"

 

3) Hydrodynamic thick film lubrication requires higher rpm, so slowing it down below spec is just asking for accelerated impeller degradation.

 

[WoodenMarker]

36 minutes ago, Enderman said:

1) Maybe on the newer corsair coolers, not on the H55.

2) The flow rate of those pumps is already extremely low. Slowing it even more is a bad idea. I highly doubt anyone who claims "minimal performance issues"

3) Hydrodynamic thick film lubrication requires higher rpm, so slowing it down below spec is just asking for accelerated impeller degradation.

I can't find examples with the H55 but the similar Thermalbench's review of the similar H75 shows ~3c difference at load between running the pump at 50% and 100%. http://thermalbench.com/2015/02/03/corsair-hydro-series-h75-aio-cpu-cooler/6/

My experience with AIO's including some H55's have showed similar performance results when undervolting the pump. 

It's hard to tell what flow rate is necessary for adequate performance but it's unlikely that the max 1500rpm is barely enough. There's probably enough headroom to safely lower the rpm and 9-10v isn't much of a drop. I wouldn't recommend going below 7v for longevity but it's speculation at best.