Asetek 645LT pump noise

definelicht

Caliper Novice
Original poster
Sep 24, 2020
24
16
I love my A4 v4.1 build (even managed to snag a Gigabyte 3070 Eagle to fit in there!), but there's one thing that keeps it from being perfect.

The pump noise from the Asetek 645 LT.
This is recorded right in front of the right side of the case, with mouse clicks for reference.

Whooshing from fans doesn't bother me, but this high-pitched, whirring sound from the pump nags me.
It's particularly noticeable when working (as opposed to gaming), when all other fans are spinning at very low RPM.

Switching to an L9 or Black Ridge would make the rig silent at idle, but this would lower my cooling potential -- which would be sad, because I love the 645LT in all other regards (I even had custom cables for the SF650 made by DreamBigByRay so the radiator doesn't squash the cables).

The only thing that has helped a bit has been configuring the header to 0%/OFF in my BIOS, which doesn't seem to change the RPM of the pump, but did reduce the electrical noise a bit (I guess due to lower voltage?).

What are people's experiences with this problem?
- Is this level of pump noise "normal"/expected from the 645LT?
- How did you install and configure the pump in your BIOS?
- Is there anything else I can do to reduce noise from the pump?
 

elvendawn

Average Stuffer
Nov 12, 2020
60
24
Hi @definelicht,

Try using Argus Monitor to set the pump speed lower, I leave my at 40% (minimum it will go) and it's basically silent at that speed, with very low to no noticeable difference in performance.

Here are some previous discussions on it:

 

definelicht

Caliper Novice
Original poster
Sep 24, 2020
24
16
Hi @elvendawn,

Unfortunately using Argus has the same limitation as the BIOS: changing the curve does not affect the RPM of the pump at all! I might try switching around the CPU_FAN and SYS_FAN headers and see if I get it to respond, but AFAIK this shouldn't matter, as they're all identical PWM headers :-/
 

elvendawn

Average Stuffer
Nov 12, 2020
60
24
Have you tried setting the fan control to DC instead of PWM? the Asetek 645LT pump is not PWM.

In my case with the Asus ROG Strix B550-I Gaming, I have mine plugged into the AIO_PUMP header and set it to DC in the Q-Fan menu. Although it's set to DC, no amount of setting the fan curve in the BIOS will affect the pump speed for me, but Argus can lower down to 40% without issue. It's not a perfect solution, but it works in my case.

Also while looking at the manual I noticed that the AIO_PUMP header is set to "Full Speed", so that could be part of my issue (and maybe yours?), I wonder if I used a controllable header that it would work differently. Currently I have 2x NH-A12X25's for GPU on the CHA_FAN header, and 1x NH-A9X25 and 1x NH-A12X25 on the CPU_FAN header so AIO_PUMP is really my only option here... I guess that is one of the issues of ITX without additional fan controllers, just not enough FAN headers to go around, even for a modest 4 fans and 1 pump.


 
Last edited:

definelicht

Caliper Novice
Original poster
Sep 24, 2020
24
16
Have you tried setting the fan control to DC instead of PWM? the Asetek 645LT pump is not PWM.

In my case with the Asus ROG Strix B550-I Gaming, I have mine plugged into the AIO_PUMP header and set it to DC in the Q-Fan menu. Although it's set to DC, no amount of setting the fan curve in the BIOS will affect the pump speed for me, but Argus can lower down to 40% without issue. It's not a perfect solution, but it works in my case.

Also while looking at the manual I noticed that the AIO_PUMP header is set to "Full Speed", so that could be part of my issue (and maybe yours?), I wonder if I used a controllable header that it would work differently. Currently I have 2x NH-A12X25's for GPU on the CHA_FAN header, and 1x NH-A9X25 and 1x NH-A12X25 on the CPU_FAN header so AIO_PUMP is really my only option here... I guess that is one of the issues of ITX without additional fan controllers, just not enough FAN headers to go around, even for a modest 4 fans and 1 pump.



My motherboard (EVGA Z270 Stinger) does not have a dedicated AiO header, only CPU_FAN, SYS_FAN, and CHA_FAN. I've now experimented with plugging the 645LT into either, but the behavior is identical.

I do not have an option to switch between PWM and DC mode. As far as I can tell from EVGA documentation, this should be detected automatically when plugging a 3-pin cable into a 4-pin header -- but apparently this is not the case :-)

I have now reached out to EVGA about this, since it might be an issue with their BIOS. I'll report back what they say.

Regarding your issue: My friend was in a similar situation, and he just used enough wire splitters so that he could plug all fans in the entire case (AiO + chassis fans) into the same header, and then used the other header for the pump. The downside is obviously that you might want a different fan curve on your chassis fans compared to your CPU fans -- but in my case, for example, I actually have the same profile on both anyway, so it would work fine.
 
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definelicht

Caliper Novice
Original poster
Sep 24, 2020
24
16
I've checked the manual of my motherboard again, and two of the fan headers are supposed to have PWM/DC toggle switches... but they don't. I have newest version of the BIOS.
Seems like the issue is on EVGA's side! Hope to get a favorable response.
 
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elvendawn

Average Stuffer
Nov 12, 2020
60
24
Well I'm glad we found you a thread to pull on, hopefully EVGA will be able to resolve it for you!

Also the "too many fans" situation is a problem of my own making, b/c I choose to deshroud the GPU and decouple those fans from the GPU fan controller. I can however get a 4 pin to mini 4 pin converter and plug them directly into the GPU to free up the CHA_FAN header, so I may try that. However I have a FormD T1 sitting around waiting till I can get a 3000 series card and I'll be doing a custom water loop at that point so I believe all I will have is two fans and a pump to plug in at that point.
 
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rcodi

SFF Gamer
Aug 5, 2017
128
90
Honestly I just put mine on the shelf and switched to a U9S since I have the space in an NCASE because I couldn't get it to a tolerable point (it sits on my desk next to me). Even when I adjusted for DC (AIO header was maxing it out so switched to manual) and lowered the speed it still had a whine, I tried reorienting it numerous times thinking that may help and that didn't work either so I gave up on it.

If anyone is wondering why I would use it in an NCASE the plan was to mount it on back rear 92mm with a windowed side panel.
 

definelicht

Caliper Novice
Original poster
Sep 24, 2020
24
16
Well I'm glad we found you a thread to pull on, hopefully EVGA will be able to resolve it for you!

Also the "too many fans" situation is a problem of my own making, b/c I choose to deshroud the GPU and decouple those fans from the GPU fan controller. I can however get a 4 pin to mini 4 pin converter and plug them directly into the GPU to free up the CHA_FAN header, so I may try that. However I have a FormD T1 sitting around waiting till I can get a 3000 series card and I'll be doing a custom water loop at that point so I believe all I will have is two fans and a pump to plug in at that point.
Out of curiosity, why didn't you plug the fans on the deshrouded GPU into the GPU fan header?
 

elvendawn

Average Stuffer
Nov 12, 2020
60
24
I have a Gigabyte RTX 2080 OC Gaming white, that card does not have full sized 3/4 pin headers on it like many Asus cards do. At the time I thought it was easier to just use CHA_FAN header on the MB instead, since no adapters were needed and since I already use Argus full time, it's easy enough to setup them up to a curve that is based off the GPU temperatures.

Now with understanding that AIO_PUMP is full speed only, I could move the deshroud fans to the GPU with mini 4 pin adapters so I could move the pump to CHA_FAN to get the correct bios behavior, but I'll just end up setting the fan curve of the GPU header in Argus b/c I'm sure the default GPU curve won't be to my liking, so not really much of a difference either way at this point. The biggest difference would be that the pump likely won't run full speed outside of Windows + Argus running.
 

luf

Efficiency Noob
Aug 30, 2020
7
3
There is a possibility that the noise is from air bubbles. With the default way a 645lt is set up there is nowhere in the system for the air to get trapped in, with the water pipes coming from the top of the radiator. I think this is why something like the losercard mod might be ideal, since it turns the radiator upside down so the inlet/outlet water pipes come from the bottom, allowing any air in the system to get trapped in the upper part of the radiator.