You should use Game Capture instead of Monitor Capture for recording/streaming, unless there is a compatibility issue which prevents you from using Game Capture. Reason being:
Game capture grabs the frame directly from the graphics card for OBS to encode before sending it back to the graphics card for final rendering of the frame.
Monitor capture has the graphics card write the frame to system RAM (Which is really slow to write/read from) before OBS grabs it to encode, then sends it back to the graphics card to render for final output.
Using CBR is not the best method for recording, CBR is best for when you are streaming to lock in a set bitrate. CQP is best as it allows the bitrate to be whatever is needed to encode and render the frame to the quality you strive for. Below is a link to JackOr's guide to recording using OBS Studio:
https://obsproject.com/forum/resour...lity-recording-and-multiple-audio-tracks.221/
Using .mp4 file format is also not the best idea as when there is a crash of OBS/system your recording is pretty much completely useless. Use .flv for single audio track recordings, .mkv for multi-track audio recordings as they will be recoverable to almost the entirety of the recording in the event of a crash of OBS/system.
Limiting your frame rate in-game will help a lot in getting the best quality out of your hardware in regards to recording/streaming. I recommend using MSI AfterBurner or EVGA Precision to cap your fps to your monitor refresh rate, or 1-3 frames higher than your monitor refresh rate will generally resolve the issue of screen tearing. Try to avoid V-Sync as it can induce input lag.
Your CPU being a 4 core with no hyper-threading will not do that well at encoding via x264. You will find the best performance with h264 (NVENC) encoder as it will take almost all of the load of encoding off your CPU and place it onto your GPU, which has a dedicated encoder chip.
Hope this helps!
