I've just finished like a 90 minute gaming session of Halo 4. Granted the game isn't very intensive when it comes to testing but I didn't have such severe FPS drops like I did previously. A few minor stutters but I imagine those are what can be considered normal (1% lows I'm guessing), didn't really impact game experience.
Will do the same test again for PUBG later as that game is much more taxing and record and screenshots the results.
As for the kind of frame drops I'm experiencing, it's like going from 144fps (game adjusts to screen refresh rate) to 20fps when entering a building for example. And it takes like 3 seconds for the screen to recover and run smooth again. I don't think these are normal because I don't remember having such big issues on my GTX 970 years ago.
"Having the 4-pin not connected in your 2nd photo shouldn't be a problem, your 5600X doesn't need it, unless Asus has designed this board different from others, so maybe look that up in the board manual." From what I read the additional 4 pin is for extreme cases of overclocking, and 5600x is only a 65W unit, if everything else fails, I'll try and connect that additional power.
Also if the graphs come clean, the additional 4 pin won't make a change, I'll uninstall that windows update as last resort.