I have been experimenting with world composition and have found that when the game loads new tiles it causes a very noticeable stutter. This occurs when PIE and with a packaged build. My current map has a lot of foliage on the sub levels but even without the foliage and just a blank landscape it still happens .
I found this old post that explains the same problem and that EPIC are working on the level streaming performance but I am not sure if I am doing something wrong (2x2km tiles too big?) or is it just not possible to have smooth loading at the moment?
Has no one else experienced this? It’s driving me crazy 
I have. I get lots of studdering just loading other levels… even small ones that are like 20 static meshes that are like 100 tri each.
I tried playing with the level streaming settings in project settings, engine, general but it didn’t make any difference.