High CPU Temperature, Faulty AIO Cooler or Dried Up Thermal Paste?

Jul 31, 2018

First time posting on here! Thanks y'all in advance!

Okay so here's the situation, my CPU temperature is pretty high on idle of 45-50°C I've recently installed all my case fans with a Corsair ML140 pro, 2 intake on the front and 1 exhaust at the back. Previously 2 of my case fan were faulty so I didn't give my overheating CPU much thought, as I'd assumed it was due to the faulty fans and poor air flow within the case however after replacing the fans the CPU temperature is still high(45-50°C)

I have a Corsair H100i v1 AIO Cooler on my CPU and using the Corsair Link and Core Temp to monitor my temps, currently everything else seems to be pretty nice and cool on idle, Motherboard and GPU temps are at a low of 27-30°C

The strange thing is that my H100i Temp is showing at a 27°C which is odd considering my CPU is at 45-50°C

Which brings me to the conclusion that whether if it's my AIO cooler is broken or perhaps the Thermal Paste has dried up? Do let me know what you think!

Oh I've also done a nice cleaning too, as I had suspected dust might be causing the high temps, but I've already cleared out the radiator etc

When I attempt to do anything remotely cpu intensive such as rendering a video in after effects or simply fast forwarding a 4k video on youtube or opening up minecraft... temperature would jump immediately to dangerously high levels of 80-100°C

Here are some details of my build incase it'll be helpful

CPU : Intel Core i7 4790k
GPU : Nvidia GTX 780 Ti
Motherboard : Maximus VII Hero
AIO Cooler : H100i v1
PSU : Corsair RM750
Case : Corsair obsidian 750d

Also why I might suspect a dried up Thermal Paste is that the pc is about 5 year's old and I have not touched the cpu since.

Thanks for the help! I look forward to hearing what are your thoughts on this!
Jul 31, 2018

Hey thanks for the respond! Ahh any idea how I could check if the pump is indeed dead? When I open up the case while the comp is on, and feel the AIO tubes I can feel a soft vibration, any idea how I could check for sure?
oh ya, in the Corsair Link it shows my H100i Pump has a 2219 rpm but I've got no idea what that means

Jul 31, 2018

Hey! Thanks for the respond! Do you mean increasing the AIO's fan speed in the bios? or all the fans in the case?

Malfunctioning H100i is quite often...I just noticed it after I googled up a bit.

good question.
You still hear sounds and see the pump speed.
Perhaps, your pump is still working but you have a clogging inside your cooling loop.
Try touching the pipes, if one is hot and the other one is completely cold, you have this problem.

BTW, if I remembered it correctly, you should have 5 years warranty for that H100i.
Corsair customer service should also still quite ok.
Care trying the RMA route? If yours is not yet 5 years old.

(Note: This one among many reason, why I am sticking with air cooler)


Dec 9, 2017
A couple of things:
1) What's the coolant temperature?
2) What's the pump speed?

One very, very common problem with these coolers is that folks fail to power them correctly. They fan header that they are connected to (usually CPU_FAN) needs to be at 100%/Full Power as it actually supplies the power for the pump and the full 12V is required. Make sure that you have this set ... not doing so can lead to issues and early pump failure.
Jul 31, 2018
Hey guys! Thank you all for your help! really apprentice it! I did clean and reapplied a new thermal paste and the temps are normal now!