If you are using Streamlabs OBS you can click "settings" then under the "General" tab click "Run auto optimizer" ... It will scan and test your system/internet speed and set optimal settings. With a 1.1 mbps upload though you are going to have really bad image quality, you might want to keep your bitrate around 1000 maybe ... It just takes some tweaking.
You can usually set your record settings higher due to the fact that you are not live streaming but i would set your record settings the same as your live stream settings, record some footage and watch it back to get a idea of what your live stream will look like to your viewers.
I have a i7 6700K, GTX 1070, 16GB DDR4 with 100MB/s download and 6MB/s upload.
Im running ...
Encoder: NVENC
Output res: 720
Rate control: CBR
Bitrate: 4800
Key interval: 2
Preset: High quality
Profile: High
Level: 4.2
Downscale filter: Lanczos 32 samples
Base res: 1080
Output: 720
FPS values: 50
EDIT: just to add, make sure to turn off Game Mode, Game Bar and Game DVR, as these all negatively impact performance.
