OBS is fantastic if you know how to adjust the settings and can even utilize multiple cores to spread out the load of work.
I don't use most of the features in OBS. I need something simple.
Then just don't use them. OBS is the most lightweight and simply designed software out there. Compare this (OBS):

To this (MSI Afterburner, something a lot of forumers have been recommending lately)

If you need help on using OBS, look up a tutorial on the basics.