[SOLVED] CPU temperature very unstable with liquid cooling

Oct 11, 2020
3
0
10
0
Hi,

I recently started my second computer build. My last one was 6 years ago. A lot of stuff changed and I'm feeling kinda noob.

I'm worried about my CPU temperature.
The temp is very unstable and varies constantly between 55~70ºc (on idle). When I start gaming it reaches up to 80ºc.
I'm new with liquid CPU coolers, but I wasn't expecting this kind of temperature.




I already changed the thermal compound but still got the same result.

My case is an NZXT h710i with the rad/aio at the top with 3x 120mm fans as exhaust, 140mm exhaust at the rear, and 3x 120mm as an intake at the front, all fans were replaced with Noctua fans.



My top fans are connected directly to the rad/aio, back and front are connected directly to the motherboard. (Initially, I had them connected to the NZXT fan controller)



My board has something called Q-FAN and has software called FAN Xpert 4. The only thing I did with these two was identifying all fans' positions and run the "fan tuning".

Here are some print screens of my current configuration inside my BIOS (the BIOS indicates that the temperature is ~47ºc):







This is a print screen of the software FAN Xpert 4 (this one indicates the same result as the Kraken z73 - labeled as CPU package):



This is my current build:
Case: NZXT h710i
CPU: AMD Ryzen 9 3900X
CPU Cooler: NZXT KRAKEN z73
Motherboard: Asus ROG STRIX B550-E
Memory: G.SKILL Trident Z 32GB 3600MHz CL14
Storage: Corsair MP600 1 TB
GPU: MSI 970
PSU: Corsair 1000W
FANS: Noctua NF-A12/A14 PWM

Questions:
1 - Is the CPU temperature normal (my last CPU was getting 40~45º on idle)?
2 - It varies 1º~10º constantly every second, is that normal?
3 - Should my fans be connected differently? Or do I need some kind of configuration?
4- How can I improve the CPU's temperature?
 
...

Questions:
1 - Is the CPU temperature normal (my last CPU was getting 40~45º on idle)?
2 - It varies 1º~10º constantly every second, is that normal?
3 - Should my fans be connected differently? Or do I need some kind of configuration?
4- How can I improve the CPU's temperature?
The temperature is normal. Ryzen constantly boosts a single core from idle to a high clock to quickly process a task and put the core back to sleep. There are dozens of temp sensors all over the CPU dies, it reports out the hottest temperature sensor at that moment. That's the temperature in one tiny part of one core during the boost so it's exactly like the temperature of a match in a room: the match is hot, but the room isn't. One match goes out and another lights, one after another, constantly, but the room still doesn't get hot.

You can't do anything about the temperature for those temp spikes when a single core is boosting at idle, it's just the way it is. Turning up the fans is like trying to put out the match by turning the AC cooler in the room. Instead set a custom fan curve that ignores the spikes as much as you can, then raise it up only as the CPU starts really working hard with many cores staying boosted almost constantly. I set my fans to a constant RPM that's barely audible up to about 65 or 70C then gradually raise fan speed to be annoyingly loud only around 80C. At about 90C it's getting really, really annoying but I also have an 85C platform thermal limit that would kick in so it never gets there. Those temperature break points seem to work pretty well for my 3700X with a 240mm AIO cooler.

I also use a long delay before ramping fan speed back down to keep them from pulsing. It's not really needed, though, as the breakpoints for the ramp up seems to work well enough.
 
Last edited:
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winwiz

Distinguished
May 13, 2009
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1
18,510
0
Hi,

I recently started my second computer build. My last one was 6 years ago. A lot of stuff changed and I'm feeling kinda noob.

I'm worried about my CPU temperature.
The temp is very unstable and varies constantly between 55~70ºc (on idle). When I start gaming it reaches up to 80ºc.
I'm new with liquid CPU coolers, but I wasn't expecting this kind of temperature.




I already changed the thermal compound but still got the same result.

My case is an NZXT h710i with the rad/aio at the top with 3x 120mm fans as exhaust, 140mm exhaust at the rear, and 3x 120mm as an intake at the front, all fans were replaced with Noctua fans.



My top fans are connected directly to the rad/aio, back and front are connected directly to the motherboard. (Initially, I had them connected to the NZXT fan controller)



My board has something called Q-FAN and has software called FAN Xpert 4. The only thing I did with these two was identifying all fans' positions and run the "fan tuning".

Here are some print screens of my current configuration inside my BIOS (the BIOS indicates that the temperature is ~47ºc):







This is a print screen of the software FAN Xpert 4 (this one indicates the same result as the Kraken z73 - labeled as CPU package):



This is my current build:
Case: NZXT h710i
CPU: AMD Ryzen 9 3900X
CPU Cooler: NZXT KRAKEN z73
Motherboard: Asus ROG STRIX B550-E
Memory: G.SKILL Trident Z 32GB 3600MHz CL14
Storage: Corsair MP600 1 TB
GPU: MSI 970
PSU: Corsair 1000W
FANS: Noctua NF-A12/A14 PWM

Questions:
1 - Is the CPU temperature normal (my last CPU was getting 40~45º on idle)?
2 - It varies 1º~10º constantly every second, is that normal?
3 - Should my fans be connected differently? Or do I need some kind of configuration?
4- How can I improve the CPU's temperature?
Tctl/Tdie fluctates (windows 10 is almost never truly idle)
But idle temp shouldn't go much above 60c...
Try running cinebench r20 with hwinfo64 running in background and report max tdie and the cinebench multicore score.
 
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jasonf2

Honorable
Oct 11, 2015
293
64
10,890
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Lets start with the obvious. The pump is plugged into the pump header and the radiator fans are plugged into the cpu fan header? Thermal paste was applied?

I am on big air on a first gen threadripper and I hold 35 when room temp is held around 73 F. I started on water thinking it was going to be great but moved back to big air because my AIO pump failed after a couple of months. It was running around 50 idle and throttling like crazy. At your temp I wouldn't be surprised if your pump isn't running. Good big air coolers do almost as well as water and are a heck of alot more reliable in my opinion, if they fit in your case.
 
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Mr.Spock

Prominent
Dec 8, 2019
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96
790
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your CPU fan duty cycle looks a bit off - you're basically doing 20% of RPM's between 25'-70', so you'll be silent but a bit slow to increase RPM's until you hit 70' and then run flat out.
believe you'll see more consistent temps even if you just up'ed middle duty cycle to 50 or 55%, this assumes CPU fan header is being used for the radiator fan and AIO pump is in the pump header
 
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...

Questions:
1 - Is the CPU temperature normal (my last CPU was getting 40~45º on idle)?
2 - It varies 1º~10º constantly every second, is that normal?
3 - Should my fans be connected differently? Or do I need some kind of configuration?
4- How can I improve the CPU's temperature?
The temperature is normal. Ryzen constantly boosts a single core from idle to a high clock to quickly process a task and put the core back to sleep. There are dozens of temp sensors all over the CPU dies, it reports out the hottest temperature sensor at that moment. That's the temperature in one tiny part of one core during the boost so it's exactly like the temperature of a match in a room: the match is hot, but the room isn't. One match goes out and another lights, one after another, constantly, but the room still doesn't get hot.

You can't do anything about the temperature for those temp spikes when a single core is boosting at idle, it's just the way it is. Turning up the fans is like trying to put out the match by turning the AC cooler in the room. Instead set a custom fan curve that ignores the spikes as much as you can, then raise it up only as the CPU starts really working hard with many cores staying boosted almost constantly. I set my fans to a constant RPM that's barely audible up to about 65 or 70C then gradually raise fan speed to be annoyingly loud only around 80C. At about 90C it's getting really, really annoying but I also have an 85C platform thermal limit that would kick in so it never gets there. Those temperature break points seem to work pretty well for my 3700X with a 240mm AIO cooler.

I also use a long delay before ramping fan speed back down to keep them from pulsing. It's not really needed, though, as the breakpoints for the ramp up seems to work well enough.
 
Last edited:
Reactions: KryptonIsDoomed
Oct 11, 2020
3
0
10
0
Tctl/Tdie fluctates (windows 10 is almost never truly idle)
But idle temp shouldn't go much above 60c...
Try running cinebench r20 with hwinfo64 running in background and report max tdie and the cinebench multicore score.
Here is my result:


Lets start with the obvious. The pump is plugged into the pump header and the radiator fans are plugged into the cpu fan header? Thermal paste was applied?

I am on big air on a first gen threadripper and I hold 35 when room temp is held around 73 F. I started on water thinking it was going to be great but moved back to big air because my AIO pump failed after a couple of months. It was running around 50 idle and throttling like crazy. At your temp I wouldn't be surprised if your pump isn't running. Good big air coolers do almost as well as water and are a heck of alot more reliable in my opinion, if they fit in your case.
Yes, Thermal paste was applied. Here is a scheme of how my fans are currently connected to the board:


your CPU fan duty cycle looks a bit off - you're basically doing 20% of RPM's between 25'-70', so you'll be silent but a bit slow to increase RPM's until you hit 70' and then run flat out.
believe you'll see more consistent temps even if you just up'ed middle duty cycle to 50 or 55%, this assumes CPU fan header is being used for the radiator fan and AIO pump is in the pump header
I changed it to 50%, can't see any improvement yet
 

jasonf2

Honorable
Oct 11, 2015
293
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10,890
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Here is my result:




Yes, Thermal paste was applied. Here is a scheme of how my fans are currently connected to the board:




I changed it to 50%, can't see any improvement yet
Sorry I completely spaced out the fact that you have a Kraken. Make sure you have the usb header, sata power and cpu header connected correctly. You need to set your curves in the NZXT Cam software not bios it has its own integrated controller.
 
Oct 11, 2020
3
0
10
0
Thanks, @jasonf2, by doing some tests with NZXT CAM software and changing CPU/fans speed to the maximum, I can certainly say that this software is controlling the CPU fans and not my BIOS settings as I previously thought it was.

It makes me wonder twice if I shouldn't connect the entire fan system to the NZXT adapter from my case as I had in the beginning.

I changed the minimum CPU fan speed to 55% like @Mr.Spock previously suggested, it seems that it has improved a little bit.

My idle temperature is now around 40º~55º, but with gaming, it still spikes up to 75º although I'm happy with that result.

I think what @drea.drechsler said is more correct, and there is not much I can do about the temp/spikes.
The best thing is ignoring the temperature and replacing the Kraken screen with an animated GIF, lol.

Thank you all for the help <3
 

jasonf2

Honorable
Oct 11, 2015
293
64
10,890
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Thanks, @jasonf2, by doing some tests with NZXT CAM software and changing CPU/fans speed to the maximum, I can certainly say that this software is controlling the CPU fans and not my BIOS settings as I previously thought it was.

It makes me wonder twice if I shouldn't connect the entire fan system to the NZXT adapter from my case as I had in the beginning.

I changed the minimum CPU fan speed to 55% like @Mr.Spock previously suggested, it seems that it has improved a little bit.

My idle temperature is now around 40º~55º, but with gaming, it still spikes up to 75º although I'm happy with that result.

I think what @drea.drechsler said is more correct, and there is not much I can do about the temp/spikes.
The best thing is ignoring the temperature and replacing the Kraken screen with an animated GIF, lol.

Thank you all for the help <3
As a general rule anything under about 80 Celsius is below throttling temperature. If you are running at 75 under full load you are fine there. The spikes you are talking about cannot in themselves be prevented, but often there is a ramp delay that can be set that smooths it out a bit depending on bios. I don't think that the kraken has a ramp delay, but click around in your CAM software and check. If it does up the fan delays (not pump) by a second or two and it will help alot. One thing I would suggest as well is turn your pump up to 100 percent all of the time. Part of the variability can be taken out by increasing the thermal mass of the heatsink on the CPU. By keeping the water flowing full bore you use as much of the thermal mass of the system as you can. Only the coolant in the heat exchanger is doing its delta magic at any given time so the more you are moving the less apt it is to change temperature quickly. Best of luck!
 

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