Question / Help Micro freezes

Ryzen 7 1800x
palit gtx 970 jetstream
16gb ddr4 3000MHz
msi b450-a pro
1 x samsung SSD
2 x older HDD

I tried to record some gameplay footage from metro 2033 redux using the x264, CBR at 40k bitrate and veryfast preset at 1080p 60fps. CPU and GPU usage is always at 40-50% max when recording but every other minute the CPU usage jumps up to something like 60% for a second, the ingame fps drop from a locked 120 to 115 and the game freeze for about half of a second. This only happens when i start recording. And so far only in the Metro redux games. Warframe, Rocket League, Patch of Exile and Overwatch all run fine while recording.

All my drivers are up to date (including BIOS)
I tried using different settings:
-other presets
-lower and higher bitrate
-CRF at 17
I use MSI Afterburner to limit the ingame fps to 120 atm. Same problem when set to 60fps or uncapped
Switched the recording path to the ssd for testing

I would very much appreciate any kind of help or suggestions to solve this problem