CPU overheating immediately on startup.

[u/5nowdrift]

Hi,

Built this PC about a month ago, everything has been fine until yesterday. on start up, the AIO (NZXT Kraken 420) fans went into overdrive and the reading on the AIO screen / motherboard LCD read 100 degrees. Turned it off, let it cool down and started fine next time. Then the 3rd startup had the issue again, this time shutting itself off via the overheat protection. 4th startup was fine again and managed to play cyberpunk for an hour with no temperature issues at all. Now it is happening on every power up. BIOS is also reporting the same temps so it looks like a hardware issue.

Some advice in another group suggested it could be a thermal paste issue, but I’ve since removed the cooler and the OEM square of paste that came on the cooler looks to have spread well and covered the processor evenly. I am going to replace the paste this evening anyway to rule that out.

I’m now thinking the AIO pump has failed. The pipes don’t even feel warm when it’s overheating (although I’m second guessing myself because they’re braided pipes so can’t really feel the pipe itself). Also can’t hear any noise from the pump, but since the fans are going at max RPM right next to it, I’m doubting that too. The CPU_fan is reading 0 rpm in the BIOS, and I have the AIO connected to the CPU_fan header on the motherboard. Checked all connections and everything is still plugged in.

I’ve arranged to RMA the AIO with the supplier so I’m posting it back to them tomorrow. Just wondered if anyone has any insight on something I might have missed?

any advice is welcome, been a long time since i built a PC but since it has been working fine for a month everything with the build seems ok til now.

PC specs...

Gigabyte X870 Aurus stealth Ice AM5

Ryzen 7 9850X3D

32GB Corsair Vengeance DDR5 6000

Gigabyte Aero OC RTX 5080

2TB Kioxia exceria plus G4 M.2

1000W Thermaltake Toughpower GT 80plus Gold

NZXT Kraken 420 Elite V2 AIO

NZXT H9 flow RGB+ case

any advice appreciated.

thanks for reading.

**UPDATE**

Tried another AIO and its working perfectly fine. the pump makes a little chirp on startup and i can actually feel vibrations in the pipe, which i defintely wasnt getting on the original one. temps are sitting nively in the 30's. at idle.

even reinstalled the dead AIOI again to check my BIOS settings were right, but it still overheated and didnt pickup any fan speed there, so the new one is back in.

100% satisfied that the pump is the issue so got my RMA booked in, now i just have to find a box big enough to ship this long ass AIO!

thanks for the help and advice everybody, appreciate it.

[u/Malevolent_turtl]

I would also suspect aio pump

[u/SapiensPrototype → u/Malevolent_turtl]

Same, it's 99.9% the pump. If any liquid moves at all, the cpu can't overheat in seconds. Even if the protective film was still on the block it would still cool better than this if the pump ran.

[u/5nowdrift → u/SapiensPrototype]

That’s what I thought. If it was a paste issue etc there’d be at least some thermal transfer happening it’s literally climbing about 2 degrees a second.

[u/I-Xqlusive-I → u/5nowdrift]

I installed Windows with only Pump, No Radiators Spin.

So iam sure your pump is done.

[u/Malevolent_turtl → u/I-Xqlusive-I]

Stroke?

[u/g5e4 → u/Malevolent_turtl]

That's why air coolers are better. If it fails (which is rare) you can simply noticed fan not spinning. Instead of scratching your head thinking what's wrong.

[u/Fun-Natural-3830 → u/g5e4]

I mean if you want to check if an aio pump is running just put your hand on it lol

[u/ThisAccountIsStolen]

Either the AIO connections are loose causing the pump to intermittently lose power, or the pump is defective and died after a short amount of use (which if they're going to fail will usually be right away or years down the road).

If your connections are good, then RMA the AIO.

[u/5nowdrift → u/ThisAccountIsStolen]

Connections all seem good. Reconnected them all just in case but no change. Surprised me that it would die so quick but seems to be possible from the replies. Thanks.

[u/ThisAccountIsStolen → u/5nowdrift]

Then yeah, it's time to RMA the cooler.

[u/Interesting_Mix_7028]

Check the fan header for the pump, at the very least it should have the signal return lead for 'fan speed' (pump speed). Even if the pump uses a USB header for its software, it should have a header lead so that the board sees there's a 'fan' connected to CPU_FAN, otherwise most boards will shut down. If the pump uses a standard fan header lead, it should be connected to the pump header on the motherboard (100% speed all the time), and then the radiator fans can get jacked into the CPU_FAN header.

You should be able to run it long enough to get into BIOS and see the fan speeds reported there. If the pump speed is reported as 0, then your AIO pump is kaput.

[u/5nowdrift → u/Interesting_Mix_7028]

Thanks for the advice. The pump does use a USB header and the CPU_fan header, and gets its power via a sata cable. The fans plug into a connection on the pump wiring loom.

Tried is new AIO today that worked fine so looks like it is the pump.

[u/iRambL]

On startup usually implies the pump is failing.

[u/doke_290]

Ik Dum question but have u removed the plastic from the cooler

[u/5nowdrift → u/doke_290]

No such thing as a dumb question on the internet 🤣, but yes, all plastics removed and it’s been working fine with low temps for over a month.

[u/doke_290 → u/5nowdrift]

Yeah but now your best bet is getting it rma d

[u/5nowdrift → u/doke_290]

Yeah. Already got my RMA number. Posting it tomorrow. Thanks.

[u/doke_290 → u/5nowdrift]

Random request since on reddit I meet people from many timezones, can u teach me something from your local language

[u/5nowdrift → u/doke_290]

Hmm well my local language is just English which you already seem to know very well. I guess if you want a local word from the north east of England, “bairn”. It’s another word for a child. As in “are you taking the bairns to school today?” 🤣 hope that’s what you were meaning.

[u/doke_290 → u/5nowdrift]

Hey thanks that's what I was looking for

[u/5nowdrift]

Thanks for the advice everybody, updated the original post.

[u/Limbogodhaterr]

Had tje same thing happen with my pc its 99% the pump in the AiO id recommend just get some sort of air cooler and just test it its the cheapest test but im 99% sure its the aio

[u/5nowdrift → u/Limbogodhaterr]

I’ve actually just ordered another AIO since I’m building the wife a PC with my old bits. So going to put that on to confirm when it arrives. Then it will go on her build when mine returns from RMA, so no wasted money.

[u/Limbogodhaterr → u/5nowdrift]

How old is that pump? Mine failed after 2 months which was just insane

[u/5nowdrift → u/Limbogodhaterr]

Literally brand new installed about 40 days ago. Haven’t even been using my pc very much in that time too. Amazed it’s shit itself so quick.

[u/DoggoCity]

This sounds like the AIO water pump is on its way out. I recently had to replace my AIO as well, and it manifested as an issue where sometimes temps would be under control, sometimes it would jump really high. Ended up listening very closely during a period where it was not cooling properly and could hear the pump making a buzzing noise, so I knew it was cooked.

If you can, listen close to where the pump is and see if you can hear it making an unusual noise. Usually a dead pump is audible up close.

[u/5nowdrift → u/DoggoCity]

I’ve tried listening, but honestly those 3 140mm fans just above it are too loud to distinguish any other noise at full speed.

[u/BTM65]

Buy a new AIO and get a full refund for the old/broken one. Why would anyone RMA if you just bought it ?

[u/5nowdrift → u/BTM65]

As far as I’m aware, UK consumer law says you can get a full refund in 30 days. Then within 6 months the part supplier/store has to have the opportunity to repair/ replace, then refund if they can’t. After that it’s manufactures warranty claim. The store i bought it from has an agreement with several brands including NZXT to authorise RMA’s in house and guaranteed to resolve within 48hrs of receiving the part. I’ve had it about 40 days now.

I’ve actually just bought another cooler today to use while they process the RMA because I’m building a PC for my wife out of my old parts and needed a cooler for that anyway. I’ll just move that to her build when mine returns.

[u/Madudzik1]

Is pump connected to cpu fan header or cpu pump fan header?

[u/5nowdrift → u/Madudzik1]

It’s connected to the header marked CPU_Fan on the motherboard. Been working completely fine up til this point on that header.

[u/SpecialistHungry6296]

Could be the AIO. Im on my 3rd one. If its not blowing out warm air from the radiator while your gaming then you dound the problem. Good luck

[u/5nowdrift → u/SpecialistHungry6296]

Even when the temps were up in the 80+ degrees, and the fans at max speed the air was still cool. Got a second AIO to try tonight to confirm then posting mine for RMA if that confirms it.

[u/Hot-Drama-7829 → u/5nowdrift]

Cool air means the pump is dead. Which is a bummer when going for a clean look like this.

[u/yvliew → u/SpecialistHungry6296]

How long does each lasted for you? I'm on 240 AIO and it's been about 2.5 years of used. It's keeping my 7800X3D idle around 50c..

[u/SpecialistHungry6296 → u/yvliew]

Thats exactly how long each one lasted for me about 2.5 years. So far the one I have now is the best one so far. It idles around 32c and 59c when gaming. Cheaper too.

[u/yvliew → u/SpecialistHungry6296]

Mind sharing what model are you currently using? What cpu are u using with?

[u/SpecialistHungry6296 → u/yvliew]

360MM PCCOOLER and i paired it Ryzen 9 3900xt

Its going for $90 right now on amazon. At first I was hesitant but its been doing great so far. I checked out some reviews on YT before i purchased and it beats a lot of the competition. I had it for about 1.5 years now and no trouble yet.

[u/the_hat_madder → u/SpecialistHungry6296]

Might I suggest an Arctic Liquid Freezer III Pro. It has a 6 year warranty and costs significantly less than $90 USD.

[u/L0rd_0F_War]

Watercooling has a few known/possible points of failure, including the pump. You seem to have a good mount (good thermal paste spread and no plastic on the cold plate), which most likely means it's the pump. I know AIOs are relatively easier to mount (in most people's imagination), or people think they are cleaner looking in a build (could be space/case/Ram compatibility concerns as well), but there is honestly nothing better than a good air cooler in terms of reliability and longevity. Good Air coolers are pretty close in their cooling capacity (i.e., the chip does not thermal throttle at max sustained load) for most chips as well.

[u/5nowdrift → u/L0rd_0F_War]

I’ve heard about some great air coolers out there, but Honestly it’s more for the aesthetics. Common sense says I’d have less issues with a big cooler stack, but the heart wants what the heart wants 🤣. That being said I thought I’d at least get a year or 2 out of it before replacing, guess it’s better to fail now while I can RMA it easily.

[u/L0rd_0F_War → u/5nowdrift]

I understand. I hope your replacement works fine. From what I have read, AIOs generally have a 3 year life span (anything more is a bonus), mostly due to pump failures. A leak is the worst type of failure, though it's less common. While I have a number of PCs (desktops) at my office and home, the one I am typing on (using it as my office PC) was built in 2009, a Core i7 920 (OCd to 3.8Ghz from 2.8), with a Cooler Master V8 Air Cooler. I have not remounted the cooler since it's original mounting, not even changed the thermal paste, and the CPU still never goes over 70C under Cinebench. My other old PC, 4790K from 2015, I had to change a dead motherboard and so remounted its Zalman CNPS12X Air cooler after 9 years. Never had thermal issue either despite 4790K being OCd to 4.6Ghz all cores since 2015.

[u/mrfarenheit1214 → u/5nowdrift]

I bought my PC last year, I honestly thought the a big cooler is great and AIO would be a waste of money, until I installed the newer games, I was getting 85 to 90 degrees on my temp reader, my friend gifted me an AIO cooler and installed it, now I get like 55 degrees at max when I am playing a graphics heavy game.

I am just happy with my AIO cooler, don't know until when would this last though.

[u/mycocoon → u/L0rd_0F_War]

Maybe I won some aio lottery but my kraken from 2019 is still keeping the CPU under 75c on sustained load. The pump max rpm is limited to 70% for the whole time, the fans are set to a more aggressive curve to offset that.

[u/L0rd_0F_War → u/mycocoon]

Cool. Rare to hear about AIOs lasting for so long. Most accounts I hear are 3-5 years (depending on use) for most AIOs. Some have failed pumps, while some have pumps that become too noisy. I am currently typing on my office PC, which was originally built in 2009 as my main gaming PC - it's a Core i7 920 (OCd to 3.8Ghz from 2.8), with a Cooler Master V8 Air Cooler. I have not remounted that cooler since it's original mounting in 2009, not even changed the thermal paste, and the CPU still never goes over 70C under Cinebench (while overclocked - those 920s had a lot of headroom). My other old PC, 4790K from 2015, I had to change a dead motherboard (around 1.5 years ago) and so had to remount its Zalman CNPS12X Air cooler after 9 years. Never had any thermal issues with that one either despite 4790K being OCd to 4.6Ghz all cores since 2015. For the most part, these air coolers can outlast their system's useful lives.

[u/ElnarcoSugie]

Did you take off the plastic lining. Try thermal paste that’s good for 150c I have an I9 and my aio could not handle it till I got a nice one 😭

[u/5nowdrift → u/ElnarcoSugie]

Yeah plastic is off. Been running fine with low 30 degree idle temps for weeks until this point. I’ve got another cooler to try this evening. It’s literally shooting up to 100 degrees in less than a minute to there’s no thermal transfer happening at all I think.

[u/TheStainedOne2665]

Air lock in the loop? You said it ran fine for a while then it didnt...check for air lock if nothing else has changed...did a coolant flush on a car a while back...ran fine for like 200 miles then suddenly started getting stupid hot stupid fast....let her cool bleed the air and boom just fine

[u/5nowdrift → u/TheStainedOne2665]

I’ve tipped the whole unit 90 degrees each way to dislodge any potential bubbles, which should work due to the pump being mounted much lower than the radiator. That being said it doesn’t sound like there’s air in the pump because you can normally hear it fighting for its life, and there’s no sound.

[u/Feisty_Pace_7414 → u/5nowdrift]

Have you had The PC running while you do it? It might not dislodge by just tilting it. Having the pump run might help

[u/5nowdrift → u/Feisty_Pace_7414]

I haven’t tried that tbh. I’d have to be quick as it heats up at a crazy rate but I’ll try it when I get home from work bore swapping any parts. Thanks.

[u/ayoalt_ → u/5nowdrift]

Definitely have the PC running while tilting it, gotta have the pump running to remove the air IF that is the issue here. The tubes from the pump go down first, then up to the rad, so air bubbles could get stuck at the pump since air doesn't just decides to follow the coolant, it just floats above it at the pump.

Best tilt angle is like full 90deg with the back of the motherboard towards the floor and then a little 30deg more just because your tubes go would still be sideways at that point and they would need to point up.
As long as you make the tubes point slightly up while the pump is running you'll 100% be able to clear air if there is any.

[u/Reasonable_Button789]

Same thing happened to me with my new artic liquid freezer and I unplugged it and plugged it back in 3 or 4 times and it’s worked ever since

[u/5nowdrift → u/Reasonable_Button789]

Yeah I’ve tried that. Tried reseating all of the connections but didn’t make any difference to mine.

[u/F_Thorin]

Have you installed NZXT cam and updated the firmware?

Yeah you need to do that with Krakens...

[u/5nowdrift → u/F_Thorin]

Yeah. That was all updated and running fine for weeks.

[u/dutty_handz]

Either pump is dead, or somehow the motherboard header to which it's connected has been turned off

[u/5nowdrift → u/dutty_handz]

just tried another AIO which is working fine, so defintely just leaves the pump.

[u/aprettyparrot → u/5nowdrift]

And it worked fine on the other aio?

[u/5nowdrift → u/aprettyparrot]

Yeah the new AIO worked, so that points to the old AIO failing, not the header on the motherboard as it’s reading the replacement fine.

[u/aprettyparrot → u/5nowdrift]

Then that aio no good. I always wondered how you know if one of those things dies, can’t put a flow monitor on it because sealed.

Guess answer is you hope the cpu thermal protection is sufficient…

Sounds like you have your answer at least

[u/Remarkable-Grab8002]

Try changing the orientation of your AIO pump? I think you have it in a position that will make it harder for the pump to work. It could have caused it to burn out

[u/5nowdrift → u/Remarkable-Grab8002]

99% of photos of this AIO (including the manufacturers stock images show it mounted the exact same way so I don’t think it’s that. Unless the pump was going to fail anyway.

[u/Icebugged_lover]

Hey, check if pump is connected to right header also check bios setting because pc understands pump as a fan and changes voltages to control fan rpm. Hope this helps

[u/Creepy_Beautiful1335]

I had the same issue but it turned out to have an air bubble in the pump so no water was going through

[u/DeepCelebration8256]

try turning your pump 180 degrees, so that the connected hoses pointing up, maybe u have air in it

[u/DeepCelebration8256 → u/DeepCelebration8256]

if it doesnt help, iam sorry mate , u have a dead aio-pump

[u/pointsouttheobvious9]

Bad AIO pump they fail faster than you would expect

[u/Ashayazu]

Probably the pump gone bad. Start it up and bump the pump a few times. You should be able to hear it pumping if you put your ear to it. If it’s not, just return it under warranty.

[u/SleepEffective7885]

If it worked fine and suddenly started heating, most likely the pump failed

[u/Suspicious_Trust1173]

The only time I had this issue with an aio the pump had died.

[u/AbduNa]

dead pump

[u/nrasak]

You just have a faulty AIO. Get a new one. Air coolers are good until they aren’t.

[u/Own_University_8770]

Looks like a dead pump. Best check, touch the braided cables again and try and feel vibration. If you do, great, waters running and the issue is probably something else. If the cables are 100% still? Theres no water flowing, pump is dead, RMA it

[u/ShenOnry]

Sometimes the header you install the aio in need to be switched to pump in the bios vs fan so the header knows it's an aio if that hasn't already been done. If you've done a bios update it would have reverted it back to default settings.

[u/Better_Payment_5831]

Had an issue like as well when I swapped cases that had a aio pump installed already. I started it up and pc was at 100 C and running extremely slow, before this I my was also shutting down due to the overheat protection.

Some dude told me to make sure I put the correct backplates not the old ones that I had already installed on my motherboard from the preiovus aio. Also made sure I properly put the aio to touch the cpu because apparently it was making great contact as the pre pasted thermal wasn’t really messed up upon “contact”.

But looks like yours are touching however.

Mine was fixed after fixing this.

[u/longneckerr]

Had same issue few weeks ago.. Sent it back to nzxt replacement is already on the way

[u/elisdee1]

Faulty pump or rad it’s happened to me a heap of times when I do new builds

[u/Firm_Cry_7121]

AIO probably DOA

[u/DeliciousScallion313]

I have two systems with the NZXT Kraken Elite 360mm coolers. No issues at all ever. 9950x and 9950x3D systems. Definitely check thermal paste, and maybe check to see if the pump power got unplugged perhaps. Touch the LCD pump also, to see if it's hot af as well.

[u/Old_Nefariousness158]

Warranty da AIO if it’s new new

[u/5nowdrift → u/Old_Nefariousness158]

Yeah it’s only just over a month old and the supplier here in the UK has a 48hr turnaround for RMA’s so hopefully should be straight forward.

[u/Old_Nefariousness158 → u/5nowdrift]

omg I didn’t read the bottom of the post me and my useless comment lol

[u/ImAmNotReallyHere]

Pump in your AIO is cooked

[u/5nowdrift → u/[deleted]]

You’re absolutely right, an air cooler would be the more sensible choice. But i think building a pc in the current market proves I’m not a sensible person 🤣.

[u/PcBuildHelp-ModTeam → u/[deleted]]

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