@puzzlezaddict I did the first step with a clean user folder. However, it will be difficult to tell really if that will cause it because like I mentioned previously, the drops are entirely random and can occur with seemingly no set specific reason.
I have my computer set to run games in high performance by default but went ahead and did it manually just in case.
Playing on ultra settings at 3840x2160, my monitor's native resolution, in the tutorial with V-sync off I was averaging 165-170 fps but with bad screen tearing as you'd likely expect from such a drastic difference in monitor capability. It would occasionally dip down to 120 randomly and back up. When it did this, there were no noticeable changes on screen. My camera angle and zoom remained the same and sims were still in conversation on the couch.
I did a clean boot on my pc and for good measure did a clean install of the game (I have tried a clean install before with no success but it never hurts to try again) Something worth noting is that the issue does seem to occur more often the longer I play on a save and I understand that likely has an effect but would make playing saves with more than 15 hours tedious.
Edit: Just for giggles, I decided to change the resolution to 1920x1080 and settings to low and my fps remained the same at 170 fps. Not sure if that is noteworthy