Local recording doesn't always work

[AlphaZero6ix]

I've just started using a dual PC streaming setup and my main gaming PC is what I'm using to locally record.

From what I've noticed, when I Start Recording, OBS will create a 0 KB file in the directory and when the recording is stopped, it'll write out the file.

I've experienced some instances that the record function won't create a file. Also, when this happens the Disk Full In (Approx) will have a negative time value instead of a true time estimate. When this happens, pressing Stop Recording won't do anything and the only way to be able to start a new recording is to exit out of OBS, go into Task Manager and force stop the OBS application.

I've tried many variations of saving the file to the SSD, having the game install on the D drive. Or saving the recording to the D drive and having the game installs on a separate drive. Running in admin mode vs regular mode. Lowering the CQ quality, from 18, to 20 to 24. Decreasing the bitrate value for the audio track.

I can't seem to know what it is that's causing the record function to NOT work every single time. There are some instances where it'll work and sometimes when it does work, and I stop the recording then restart it for the next game, it won't work.

Has anyone else noticed this happening?

p.s. I'm recording at 120FPS, not sure if that matters, but I think my hardware should be able to handle it.

Here are my OBS and Recording settings (for reference)

Base Resolution : 1920x1080
Output Resolution : 1920x1080
Fractional FPS : 120/1

Recording Path : D:\OBS
Recording Format : mkv
Encoder : NVENC
Rate Control : CQP
CQ Level : 18 (or 20, or 24)
Keyframe : 0
Preset : Max Quality
Profile : High
Psycho Tuning : On
Max B-Frames : 2

MOBO : MSI X570 TOMAHAWK
CPU : AMD 3800X
GPU : 3060 Ti
RAM : 16 GB
OS DRIVE : M.2 1TB
DATA DRIVE : 3 TB 7200RPM SATA DRIVE
GAME INSTALLS on C:
OBS INSTALL on C:
OBS RECORDINGS on D:

Attached a log file that shows....

14:41:27.667: ==== Recording Start ===============================================
14:41:27.667: [ffmpeg muxer: 'adv_file_output'] Writing file 'D:/OBS/2021-01-27 14-41-27.mkv'...
14:43:17.792: Stopping recording due to hotkey
14:45:18.677: ==== Shutting down ==================================================

A recording that works would show the file being written

14:33:41.505: ==== Recording Start ===============================================
14:33:41.505: [ffmpeg muxer: 'adv_file_output'] Writing file 'D:/OBS/2021-01-27 14-33-41.mkv'...
14:34:23.159: [ffmpeg muxer: 'adv_file_output'] Output of file 'D:/OBS/2021-01-27 14-33-41.mkv' stopped
14:34:23.159: Output 'adv_file_output': stopping
14:34:23.159: Output 'adv_file_output': Total frames output: 1734
14:34:23.159: Output 'adv_file_output': Total drawn frames: 4994 (4999 attempted)
14:34:23.159: Output 'adv_file_output': Number of lagged frames due to rendering lag/stalls: 5 (0.1%)
14:34:23.159: Video stopped, number of skipped frames due to encoding lag: 5/4997 (0.1%)
14:34:23.178: ==== Recording Stop ================================================

 

[AlphaZero6ix]

I've done more testing and discovered that when recording to flv, then there's no issue.

Which leads me to believe that at 120 FPS, recording multiple audio tracks is problematic?

Once I switch back to mkv recording but only 1 audio track, then the problem doesn't occur and I'm able to get a recording file written out every single time.

Could there be an audio bandwidth limit? Since my in-game audio (or Desktop audio is at 320 kbps) and my mic/discord audio track is at 160 kbps? For a total of 480 kbps audio being processed in 2 audio tracks vs only 320 kbps from 1 audio track??