High water temp, low cpu temp

[Drozee]

Hello everyone. Recently my custom build has been starting to run pretty loud. The noise originates from my H100i, trying to cool my i9-9900K OC to 4.2.

 

I've always had my H100i fans turned on "quiet" in iCUE without any problems. My CPU temp is steady 27C, and spikes to 43C during a Cinebench test.

 

However! Im noticing my "Temp" on my cooler in iCUE sits at 50C. I've tried googling it, and apparently its the water temperature shown, and quickly figured out it could be a contact between the CPU and cooler, or a broken pump.

 

Now i've cleaned the contact plates with isopropyl, and applied a new "rice corn" of thermal paste. I turned the beast on and it was silent again! I touched the tube with the water running through, and could barely feel the stream.

 

That was until 2 min after the PC was turned on. Now it's loud again, and i can clearly feel the water pumping through both tubes again. iCUE is staying at 2700-2750 RPM, and im now out of idea.

 

Does anyone know what else it might be?

 

[Drozee]

Picture of the temps.

[For Science!]

34 minutes ago, Drozee said:

Picture of the temps.

eh that's kinda weird. No direct answer for the hot water temp, but lets start off with some basics.

- Is the H100i platinum powered by a fan header?

- If so, which fan header have you plugged the pump block int?

- Furthermore, what kind of fan curve, if any have you set the header to.

 

Normally these pumps require a constant 12 V voltage for operation, and it looks like the pump is bouncing around a bit which suggest that the voltage is also bouncing around. 

 

And since I'm asking stuff anyway, just wanted to check you did mean a 4.2 OC (which is actually an UC).

[Drozee]

• The H100i has its own connector for both fans (so 2 turns into 1) - which is then plugged into the CPU_FAN slot. Looking at my motherboard manual (Z390-F), it is max 1A 12W, so that is 12V yes.
• The fan curve is actually a default one called "quiet", where you cannot see the curves. I can try making a custom curve myself, but it's worked fantastic over the last year on the "Quiet" setting.

The bouncing around in the graph i linked is probably because of the cinebench testing i did. Right now it sits stable at 51C.

[For Science!]

1 minute ago, Drozee said:

• The H100i has its own connector for both fans (so 2 turns into 1) - which is then plugged into the CPU_FAN slot. Looking at my motherboard manual (Z390-F), it is max 1A 12W, so that is 12V yes.
• The fan curve is actually a default one called "quiet", where you cannot see the curves. I can try making a custom curve myself, but it's worked fantastic over the last year on the "Quiet" setting.

The bouncing around in the graph i linked is probably because of the cinebench testing i did. Right now it sits stable at 51C.

The pump has its own firmware that controls the fan speed, the CPU_FAN slot by default has a voltage/PWM curve based on CPU temperature, so I would recommend setting the "fan speed" of the CPU_FAN slot to 100% across all temperatures. This would ensure you give the pump 12V at all times, at the moment it is probably on DC control and so only receiving 12V when the CPU is very hot 

[For Science!]

Basically my base hypothesis at the moment is that the when you turn the PC on, the BIOS starts by putting all fans to max briefly (at least some of my motherboards do this), during this time the pump receives 12V and behaves well. However after the POST sequence, the BIOS detects that the CPU is actually really cold (since it is quite heavily underclocked) and based on your quiet fan curve, does not send adequate voltage to the pump which may or may not be causing funky issues.

 

Asetek pumps need the 12V supply for healthy function and actually has nothing to do with the fan speed, since that is controlled seperately by the firmware. There may be a misconception here that you are simply "passing through" the motherboard connection to the fans, but this is incorrect. The 3-pin fan header coming off from the block is purely to power the pump (this needs constant 12V), and the pump's firmware sends out a PWM signal through to the 2 4-pin fan headers where you plug the fans into.

 

Both pump speed and fan speed are controlled through software in iCue and should not be attempted to be regulated through voltage tweaking.

[Classified101]

It seems you're not the only one with this issue. I did some google search and found these.

Maybe these will help.

https://www.reddit.com/r/Corsair/comments/9vtcf6/h100i_v2_safe_liquid_temp/

https://linustechtips.com/main/topic/968279-corsair-h100i-v2-water-temperature/

https://forum.corsair.com/v3/showthread.php?t=182244

https://forums.tomshardware.com/threads/cpu-temperature-extremely-high-with-h100i-v2-liquid-cooler-after-bios-update.3209814/

 

Yes, the liquid temperature is unusually high. I have a Kraken x62 and my liquid temperature stays around 33 degree Celsius with an ambient temp of 25 degree Celsius.

 

But I don't know what the safe range is for your AIO. I don't think this is a pump issue because if that were the case, the CPU will definitely overheat.

 

Bitwit recently made a video on this very topic.

 

[Drozee]

I see. I check BIOS, and everything seems fine. But i did notice, the fans first go crazy once i boot into windows. 

 

Also - the i9-9900k is by default at 3.6, but i found out i actually OC to 4.3 and not 4.2 (but whatever). Minor detail 

 

Ill check at those links you send "Classified101". Thanks

[Classified101]

8 minutes ago, Drozee said:

I see. I check BIOS, and everything seems fine. But i did notice, the fans first go crazy once i boot into windows. 

 

Also - the i9-9900k is by default at 3.6, but i found out i actually OC to 4.3 and not 4.2 (but whatever). Minor detail 

 

Ill check at those links you send "Classified101". Thanks

you're welcome. Do tell us if it's resolved or not.

If nothing works, you can contact Corsair and see what they say.

I think they have a five year warranty on their AIOs . Correct me if I'm wrong.

So even it's an hardware issue, you can use the warranty and get a replacement.

 

[Drozee]

So far nothing. I haven't solved it yet, but i have noticed something weird though.

 

I tried setting the H100i fans to fixed 700RPM, so it wouldnt go crazy at the 2700RPM (from Quiet mode). And nothing happened with the temperature. So i did a couple of cinebench tests, and somehow the Temp now fell by a couple of degrees.

 

Ill send an e-mail to Corsair. 

[For Science!]

12 minutes ago, Drozee said:

 

See what they say, something has to be wrong, either the fluid temperature sensor or the cpu sensor. It is not physically possible that the cpu is colder than the fluid.

[Drozee]

Hmm i JUST thought of something. I don't know where the sensor for the liquid is located, but maybe my GPU is blasting hot air onto the sensor? There's nothing between the GPU and CPU block, and the iCUE H100i temp is pretty close to the temp of my GPU (my GPU runs between 47-53C and entire rest of my setup 25-30).

 

EDIT: I'll make a long GPU benchmark, and see if the coolant temperature get's semi close to the GPU temp.

[For Science!]

7 minutes ago, Drozee said:

Hmm i JUST thought of something. I don't know where the sensor for the liquid is located, but maybe my GPU is blasting hot air onto the sensor? There's nothing between the GPU and CPU block, and the iCUE H100i temp is pretty close to the temp of my GPU (my GPU runs between 47-53C and entire rest of my setup 25-30).

 

EDIT: I'll make a long GPU benchmark, and see if the coolant temperature get's semi close to the GPU temp.

Dont think so. The sensor should be in the pump block.