I'm having the same basic issues. I have noticed here and in bug reports that many people are having what appears to be the same symptoms but I have yet to see even a single theory much less a fix. I'm going to start posting in these threads to at least let people know they arent alone in this as it kind of feels like they are if you just go thread by thread.
Here is mine
https://answers.ea.com/t5/Technical-Issues/Post-Patch-FPS-Stuttering-Low-GPU-Utilization/m-p/7279972#M5787
One thing Id ask to check if you can is your GPU usage. If you dont use Afterburner, Windows Task Manager itself actually has a basic GPU utilization graph under the Performance tab. Play a game and see what value you get there. It should be basically 100% (as it is in single player, the game menu, and pre-patches). Low GPU utilization hardly leads to any logical conclusion without more information but its a huge red flag that indicates a serious problem at the same time and is an important metric.