Strange 8700K temperature spikes after boot

Nov 17, 2018
I built a pc about 1-2 weeks ago, these are the specs:
- Intel Core i7 8700K
- Gigabyte GeForce RTX 2080 GAMING OC 8G
- Gigabyte Z370 Aorus Ultra Gaming 2.0-OP - 32GB Intel Optane
- 2x 8GB 3200 MHz G.Skill Trident Z RGB ram
- Cooler Master MasterLiquid ML240L RGB cpu cooler
- Corsair RMx Series RM850X (2018)
- Phanteks Enthoo Evolv X case
- Samsung SSD (500GB) and Seagate HDD (2TB)

I have not overclocked the CPU. I am using the standard settings and the frequency is at 4300 MHz (which was the default). Max core voltage seems to be at around 1.25 V or something, I'm not sure since the voltage keeps changing.

I have been using it for about 2 weeks now, and everything has been perfect. Great performance, great temperatures. The CPU temp idles at around 22 - 25 degrees celsius and everything works perfectly.

However, a couple of days ago I booted up my pc and really soon after that I heard my CPU cooler getting louder and louder, so I checked my cpu temps using CORE TEMP. For some reason, without much load as it had just been after boot and I wasn't doing anything yet, my CPU temperatures were spiking to as high as 80+ degrees. I checked task manager and there were no heavy cpu tasks or anything out of the ordinary, so I got startled and rebooted my pc. The temps then were still sitting at about 50-60 degrees. After checking task managers again and deleting some tasks it dropped down to the usual low 20's (it wasn't a specific task that tortured the cpu, I just randomly closed some tasks and after a while the cpu went to back to normal). I went on google and searched a bit but couldn't really find anything. My temperatures were fine again and I stopped thinking about it.

However, now it is every time I boot after at least an hour "off time" that this problem again occurs. Very high CPU temperatures, going into the 80's, while I'm not doing anything. So every time I boot my pc now, I open Core Temp and task manager and begin closing tasks which are not neccesary until my temperatures drop from these weirdly high numbers to the normal 22 degrees celsius. This usually takes a couple of minutes, and it doesn't honestly seem like closing tasks helps but I feel like at least then I'm doing something. Even in games, like black ops 4, I don't reach these high temperatures so I don't understand what the problem is. Also when stress testing with Prime95 I get lower temperatures then what I get when I do nothing after launch. Note: When playing black ops 4 my cpu temps almost NEVER touch 60 degrees C. This shows that the temperatures I'm getting after boot really are strangely high.

The first picture is of the Core Temp screen during my normal (idle) temperatures. I wondered if these high temps were caused by a startup program and launched into the bios to see if the temperature there would just be normal. This was the case the first couple of days when I built the pc, the temps in the bios would always be around 24 degrees, however today when I was again stressing out because I was getting very high temps, I thought let me check the bios, and that's where I made the 2nd picture. As you can see the temperature was rising from boot, up until about 45 C and then dropped to an idle temp of 24. The next time I get the high temperatures I will make a screenshot of core temp and put it here.

To me it looks like my CPU cooler is malfunctioning, perhaps it takes some time for the pump to activate?

What can this be? Any help will be greatly appreciated.