CPU on Limits

[Kaiser Wilhelm]

Hello, i have a problem but I can't find any solutions so I'm asking here. 

I feel like my PC performs worse in games than 6 month before. I have 130 fps in Battlefield 5 but somehow the game is lagging, stuttering and sometimes I have no ingame sound, additionally my team speak 3 starts acting weird, I loose connection to my Server. That didn't happen a few months ago. CPU utilization is almost consistent on 100% when in game or when I start a new programm.

 

My system:   i5-7600k 4x4,5ghz  (OC)

                        MSI GTX 1080 OC

                       16 GB 3000MHZ

                       Build it myself 1 year ago

 

Options I've tried:

- OS update and new installation 

- all affected games reinstalled

- all drivers updated

- cpu overclock from 4,2 to 4,5ghz (runs stable, but very slight improvement 

- cpu and GPU benchmarks are a bit higher than average

 

So does anyone have any ideas what could be the problem or have any solutions. I really don't know what I could do anymore than upgrading (which i can't afford)