Unstable bitrate and dropped frames when streaming

[purfectace]

Hey everyone, I've been having this problem for a while now.

Whenever I start streaming on Twitch, I get very big fluctuations on my bitrate and my stream gets choppy at first and then drops to oblivion, to say the least, and I can't figure out why. I've tried streaming to YouTube, it seems fine for the most part, though I did have some frame drops last time I checked. I've contacted my ISP and they say that there's no problem on their end, so it could possibly be something on my computer.

First things first, the computer specs:
CPU: Intel Core i5 13600KF
MOBO: Gigabyte Z690 Gaming X DDR4
RAM: 32GB DDR4
GPU: Gigabyte RTX 3060ti
OS: Windows 11 (freshly formatted)
I've tried streaming with ethernet connection, with Wi-Fi, and also from different computers. It should be noted that I've had this issue since around mid-July, with a different internet service provider, also I've port forwarded the required ports on windows, since my router doesn't have any option to port forward. Also, I'm not running an antivirus while streaming.

The internet:
300Mbit down, 30Mbit up

As for the OBS settings, I'm using the recommended settings from Twitch (note, my resolution is 2560x1440, but I've downscaled to 1920x1080 @ Bicubic, 16 samples):

I'm running OBS as administrator, I've disabled Hardware-accelerated GPU scheduling, I've also tried enabling it back, I've set OBS Studio in High Performance in Graphics Settings as well as NVIDIA Control Panel, I've disabled IPv6 from my network adapter.

When I begin streaming, everything is ok. But after I boot any game, from WoW Classic to Dead by Daylight, to Resident Evil 3, after a few minutes the bitrate starts to go crazy.

I've also tried the Twitch Bandwidth Test tool and I'm getting good ping and quality on 2 servers only.

From what I've noticed, and I don't if it's normal or not, my encoder usage is a lot lower that I've expected. Notice that the Video Encode graph drops after my game (DbD) hits 97% usage on 3D. Is this normal?

I'm including a log file, in case anything helps. Any tip or help will be greatly appreciated!

 

[PaiSand]

The issues on the network connection most probably is an issue on your ISP.
But first check your local network, cable, router/modem
According to the log file the connection between the computer to the router/modem is just fine.

About the GPU, some games use a lot of the GPU power, and if you add to it other programs that use the rendering side of the GPU, you get this.
The encoder is a separated part on the GPU, so you don't see it there.
You have 5 game capture sources on a same scene. Make 1 scene per game source. Normally you only need one game capture for all the games.

Enable Windows Game Mode as it do helps. Do NOT enable HAGS.

Analyzer | OBS

OBS (Open Broadcaster Software) is free and open source software for video recording and live streaming. Stream to Twitch, YouTube and many other providers or record your own videos with high quality H264 / AAC encoding.

obsproject.com

 

[purfectace]

Today, I enabled Game Mode, made sure that HAGS is disabled via regedit, and only used one game source. Also from OBS settings set the Process Priority to High.
I also tried the following:

1. I made a scene, with just a text source ("Stream is starting shortly") and left it there for about 5 minutes. No frame drops, but speed did fluctuate from 6000-6300 (if that's normal then ok).
2. I made another scene with just one game source, booted a game, and then added the game to that source. After a few moments, frames started to drop and bitrate fluctuated to 4000-7000.
3. Without closing the game, I switch to the Stream is starting scene, and after a few moments, frames stopped dropping and bitrate went back to 6000-6300.
4. Switching back to the game scene, frame drops again. Then back to the text scene, went back to no frames dropped after a minute.

I don't know if this has to do with either my computer or the ethernet network adapter pushing packets to the network the wrong way or my ISP, but as I said I've had this problem with two different ISPs and different houses.

Are there any possible network options I may have to check?