Yes, I read the log and the first thing I did was Google the processor. I really hate to a judge a book by it's processor, but they not be in a situation to purchase a RTX 3800 for video encoding, so make some lemonade with that lemon.
You can try not making any changes and expect a different result, but that's insane. All of those changes are free and Windows 10 1709 is no longer supported. At least update for security reasons.
Try the following recording settings:
Type: Standard
Format: mkv
Encoder: x264
Rate Control: CRF
CRF: 0
Keyframe: 0
CPU Usage: ultrafast
Profile: baseline
The file is going to be huge (because it's lossless) for the duration but you can re-encode it later using Handbrake, VLC, etc. In my test (2.9 Ghz 4 core) this used less CPU than veryfast CBR at 2.5 Mbps.
If that is using too much CPU try:
Type: Custom Output
Output Type: Output to File
Container: EDIT: matroska (Video)
Video Bitrate: 10000 Kbps (adjust as needed, this was 720p 29.97 FPS video)
Keyframe: 250
Video Encoder: mjpeg
Audio Encoder: aac
OBS used 10% cpu with that on my system