Question CPU % increases over time, spikes up to 100%, then "reboots" to 10% lagging the whole system

Jul 25, 2022
Hey there, I've been playing some rather new games that shouldn't be a problem for my new system, like The Cycle: Frontier and Apex Legends and have been noticing something rather weird lately.
After I put my new Graphics Card, a RTX 3060, into my case I noticed that my CPU seemed to have trouble, because my games would have weird lag spikes. When I watched the CPU via Task Manager on my 2nd Monitor I noticed that my average % slowly creeped up, until it eventually reached 100% and then my pc lagged for around 4-5 seconds, and putting the CPU back to around 10% usage. It would go up to the high average % again, reach 100% and re-do the whole process. The average % increases depending on how long I used my PC for and what I used my PC for. Anyone got any Idea how to fix it? It really annoys me when I play because I get random lag spikes that severely impact gameplay.

PC Specs:
RTX 3060
Processor Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz, 4008 Mhz, 4 Core(s), 8 Logical Processor(s)
16GBx2 HyperX DDR4 RAM
Motherboard B150M PRO-VH (MS-7996)

If you need anything else, feel free to ask
Jul 25, 2022
check cpu temp?
malware scan the system?
brand and model of the psu?

check hdd/ssd usage?
how full is the ssd?

After a bit of playing (and having the PC turned on for 11+ hours at this point) the max temperature is 90°C, at which the stuttering/lagging occured. The temperature started around 70-75°C average when I started playing and then went to around 75-80°C average a little while after. So I assume that I need a better cooling method?
Malware scan = Nothing
Brand and Model of PSU: Thermaltake Smart RGB 700W (I know, I know, I was low on money)
HDD/SSD Usage is fine
SSD is at 50% (Windows is on SSD too ofc)

Edit: I also had a lot of Opera GX tabs open, and stuff like that, for a good stress test, maybe you need to know that