Classic FPS drops at the start of combat

Hi, I have a 2080ti and an 17-9700k and I been noticing some FPS drops in my raids and my m+ dungeons, but it seems to only happen when 1, it is the start of the raid ... for example once the pull timer hits 0 and everyone starts my fps drops from like 90-100 to 20-30 and sometimes worse to the point I can barely even move my screen or play. The second time my FPS drops really low is when there are a lot of adds or nameplates, for example tindral when they spawn the roots. Whenever the roots spawn on tindral my fps goes to like 15 and I can barely get an eyebeam off as a demon hunter. I use a decent amount of addons, such as elv ui for interface ui, plater for nameplates, and weakauras ... most of the other are lightweights like raider.io, details, gtfo, and dbm, and a couple other small lightweight add ons. I can see the nameplates being an issue in aoe pulls, but I don't understand how it would be an issue in ST fights or the beginning of a fight. I want to also add that I tried dx11, and dx12, I use the lowest settings possible, and my view distance is low, nameplate distance is low, and I have nameplates for friendly's turned off... only enemy nameplates are on. This has been an ongoing issue for me, but it seemed to get progressively worse over this recent patch, mayb it could be because not all my addons are updated yet, but never the less pre patch I was still experiencing fps drops in raids and m+ just not to this extent where it is almost unplayable in certain instances.Edit: Just to add I am referring to retail wow via /r/wow https://ift.tt/5fmDhn7