Question / Help Very low framerate when I record Overwatch using obs

[popasion]

CPU: I7-9700kf
GPU: RTX 2080 SUPER
RAM: 32G

Framerate in game is over 170, but the fps of the video I recorded using obs is very very low(I guess lower than 20).
And I think the

Here is my log, if it could help.

https://obsproject.com/logs/3oCYB3T1r43dhhNb