I know you asked for settings, but that isn't straight forward. Absolutely start as AaronD mentioned, but, beyond that... it depends
So, Beware your expectations. That is an 8-generation old Ultra-low power laptop CPU, subject to thermal throttling, optimized for battery life, not the computationally demanding task of real-time video encoding. Worse, Per a response from Aug 2020 in this forum, the GeForce 820M does NOT have NVENC, so you'll be using CPU encoding (a bad thing for you).
So, you should be looking for optimizing your Operating System and OBS for an under-powered system, a topic for which there are numerous threads on this board .... though as much art as science. depends on your exact system, and workload (in WAY more detail than you described in original post).. do NOT expect figuring this out to be easy nor quick.
starting point
- disable/exit/turn off as much background processing stuff at OS layer as possible. (What exactly? it depends). Beware auto-started apps that aren't absolutely necessary. Get your system working stably with OBS, then you can test with turning items back on..
- in OBS, start at 30fps, don't rescale if you can avoid it, don't use OBS' Studio Mode (2X rendering workload).
Personally, I'd have switched from that SATA HDD to a SSD long ago. And only 4GB RAM is going to limit you (not sure how badly).. and I didn't bother to look up if you can upgrade... and not sure worth it at this point.. maybe?? depends.
I recommend monitoring hardware resource (CPU, GPU, RAM, Disk I/O, etc) utilization [for ex. using Task manager’s Performance tab and/or Resource Monitor] to see if your system is being maxed out with your settings
https://obsproject.com/wiki/General-Performance-and-Encoding-Issues and
https://obsproject.com/wiki/GPU-overload-issues
