Question how can i stop window capture from lagging?

[xxGreedxx]

i have a rtx 2080, a i7-8700, and on streamlabs obs anytime i use window capture my game feels choppy, but i still have 400+ fps in a low power io game, it completely ruins the experience and ive had that problem for as long as i can remember and have never found a working fix, im considering forking over a wad of cash and using an elgato with my laptop.
CPU: i7-8700 3.20ghz
Motherboard:B360m Extreme
Ram:xpg 2x-8gb
SSD/HDD:samsung 250gb ssd, seagate 2x 2tb
GPU:rtx 2080
PSU:corsair 850w 80+ gold
Chassis: not sure
OS: windows
streamlabs obs settings:
Encoder: x264, nvenc also has the same issue
Bitrate: 3000
most cpu and gpu settings set on veryfast (lowering these settings also doesnt fix the problem)
process priority: above normal
game: Krunker
games that i can use game capture for, do not have the problem, only when im playing a game where window capture is my only option

 

[Lutfij]

Might want to list your specs for us to get a better image of the situation. List them like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:

Mention the game you're using and the settings you've chosen for OBS.

 

[xxGreedxx]

Might want to list your specs for us to get a better image of the situation. List them like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:

Mention the game you're using and the settings you've chosen for OBS.

updated the post, hope that helps you figure out what could be the issue