I have no idea how,but this made wow more smooth for me,faster loading screen and so on.It also completely removed stuttering.
I guess it became corrupted in my case,so wanted to share this with you.It might help someone as well.
Press Windows Key+R and type %programdata%>Nvidia Corporation>NV_Cache and delete everything inside.I do this everytime before logging into game.
It’s so refreshing seeing problem solved in contrast to bugs, but…
seems more like workaround rather than actual fix though.
Dont think its needed to do it everytime before logging,its just me… 
Which video card and driver are you using?
There could be or still is a driver conflict or some problem with storage getting close to full capacity.
You can run Latencymon, then running the game and alt-tabbing to Latencymod when the game stutters - if it’s all red then likely there is a driver conflict - like Nvidia driver with audio drivers. The solution is to wipe Nvidia drivers with DDU and then doing a fresh install. Also updating all motherboard drivers is advised.
To check storage or other general problems you can run userbenchmark and check each component percentile result that compares result against other results of same piece of hardware. If something is way below then there may a problem with it.