Question CPU temperature going very high after applying new thermal paste

[Gottoms]

So here is my story :

Today I applied new thermal paste for the 1st time on my CPU. I was kind of anxious about doing this but everything went well until one point. Some of the old thermal paste that I was trying to remove had built up next to the big metal cover and kind of touched under the CPU. Like, on the surface that is in contact with what's on the motherboard. I tried wiping it off with 70% rubbing alcohol, I reapplied new paste, then booted my computer. I don't know if this is normal, but after pressing the power button, my computer powered up, then shut down a few seconds after, about 2-3 times. Then, it finally booted into the American Megatrends boot screen saying something like "Overclock failed". I simply didn't know what to do so I logged on my computer normally, to notice its fans were going crazy. Task manager was showing that some basic processes at startup were using a lof of power as well as CPU. The fans calmed down after a bit, and now, during idle, the core temperatures are around 50 celsius (120F). But whenever I open any application, the fans begin to rotate like crazy again. Also, the core temperatures soar to well over 100 celsius when I run Battle.net. My FPS also dropped by a lot compared to before applying new paste.

Some basic info about my computer:
CPU: i7-4790K
GPU: Nvidia GeForce GTX 1660 Ti
RAM: 16 Gb DDR3
PSU voltage : 650V
CPU cooling system: Cooler Master Seidon 120

Here is some screenshots of the core temperatures

Idle

While running Black Ops 4

Thank you for your help.

 

[Lutfij]

Always list your specs like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:

We will need the make and model of your PSU inclusive of it's wattage. FYI, I think you meant to say 650W and not 650V. Can you keep an ear open towards the cooling pump/block and see if you hear any bubbles being hit by the impeller? AIO's tend to have a small bubble lodged in the unit and when it ends up in the pump unit, can cavitate or worse damage the impeller. YOu can also expect some coolant to evaporate over time. Which leads me to ask, how long has the cooler been in your build?

 

[Gottoms]

Thank you for the fast replies and corrections.
Right now I can't hear any bubble-ish sounds coming from the cooling system.
I've had the cooler for about 2.5 years now, when I bought the computer. It's been working just fine until today.

 

[gasaraki]

You didn't mount the cooler back on correctly. 50C at idle is too high. Don't know why you had to reapply thermal paste for no reason.

 

[Gottoms]

You didn't mount the cooler back on correctly. 50C at idle is too high. Don't know why you had to reapply thermal paste for no reason.

Sigh, I got told by multiple friends to replace the paste as it could be one reason why my GPU isn't working at its intended power, if the CPU is underclocking due to higher temperatures. As for the cooler rack, I'll try to place it back on, but it's difficult to do it alone as some parts need to be held in place while screwing in some other parts.

 

[Gottoms]

You didn't mount the cooler back on correctly. 50C at idle is too high. Don't know why you had to reapply thermal paste for no reason.

Well, I just unscrewed the cooler and rescrewed it back in place, and the core temperatures have dropped to around 80-90 F at idle, and the fans are working perfectly fine, not a single one went crazy. The core temperatures are doing fine as well when playing Black Ops 4. Looks like this just solved my issue. Thanks a lot!

 

[Gottoms]

You didn't mount the cooler back on correctly. 50C at idle is too high. Don't know why you had to reapply thermal paste for no reason.

Actually, after re-positioning the cooler, the temperatures dropped back to normal. But this time, the CPU usage was at 100% when playing games. I went to the computer store later today and had an expert look at my computer. He inspected my CPU, and even made an adjustment because my CPU fan was plugged in the wrong slot. For him, my CPU was running correctly & the temperatures were normal. But when I came back home, the CPU temperatures spiked back up to 40+ celsius on idle, and up to 100 celsius when running games...is there something that I'm doing wrong?