H150i Temps with 9900k got really bad over time

[TheRgbGuy]

So i build my pc 2019 with an i9 9900k an corsair h150i aio (at start 3x 120LL later upgraded to QL) and in a bequite darkbase pro 900 rev2.
I also removed the front so completely open and i got 3x 140mm QL fans in the case so should be pretty high airflow.
All temps measured at around 21-22°C room temp and the 9900k is stock, no oc.

Back when i built it the temps where "fine". Idle around 35°C liquid and 42°C CPU,
while gaming (~35% cpu usage) 45 liquid and around 70-75°C cpu and
with high load like prime95 after 10min or so around 55°C liquid and 95°C but still 4,7ghz so no throttle.

i guess fine for a 9900k from what i have heard. I didnt really look much on temps since then, yesterday i reset my pc and while testing some games i was pretty shocked to see the cpu temp at 95°C, liquid at 67°C and cpu throttled to 3.4ghz....... while like 40% usage.

I did some further testing with the intel xtu and some static load (100% usage with prime95).
During the following tests all fans where 100%, the pc was cooled of before (33°C liquid at start) and the pumpspeed in icue was shown at 3000mhz in the preset intense.

At stock cpu ~120w, the pc shut of after 5 sec and hitting over 100°C cpu......
Locked to 100w limit, after a couple seconds 95-98°C CPU after one minute 58°C liquid (from 35 before)
Locked to 75w, stayes at around 80-87°C for a couple minutes but after like 10min starts going to around 90°C.

Aio broken?
I checked thermal paste looked fine and repasted it but same results.

Nice.......i mean i like corsair products specially icue and bought heavily into the ecosystem but i am really disappointed, over around 3 years, i had 4 LL fans fail (3x LED flickering and one motor dead) and multiple lightstrips as well as one ls450mm fail (cant control them anymore after a certain led, probably internal connection between leds broken)

[LeDoyen]

when the computer has warmed up, if you touch the tubes coming from the pump, are they roughly the same temperature or do you have one that is much hotter than the other?

if there is a big difference, it's very possible your coldplate is starting to clog.

Another test would be to let your PC idling and see if the water temperature steadily increases, slowly.

No need to try prime95 at this stage actually, the AIO seems to be toast, so don't overheat your CPU.

My guess is you'll find a big temperature difference between the tubes, and from what you said, the thing idles hot already.. so you should open a support ticket with Corsair directly.

https://help.corsair.com/hc/en-us/requests/new

You are well within the 5 years warranty, so, with those little tests you should be able to get a replacement under RMA.

[c-attack]

22 hours ago, TheRgbGuy said:

Locked to 100w limit, after a couple seconds 95-98°C CPU after one minute 58°C liquid (from 35 before)

Anytime your coolant temperature shifts that fast, something is wrong.  I agree with the above and it is likely there is some type of flow problem.  Contact Corsair Support or use an alternative cooling method.  This problem will get worse with time and try to avoid heavy sustained loads.