Can be reproduce by spawning in multiple (big?) ships in succession. The 1st one should load fully and at a decent speed. The 2nd and 3rd one will most likely load a part of it and then grind to a slow crawl,It's mostly fine. sometimes they just stopSectors may even loading completely faster now.
Entering a sector with many ships should trigger the same,There's however a delay in it, the first 2-3 seconds after entering a sector, nothing loads. seems that it can't handle multiple ships at onceAfter that it's fine.
That delay doesn't really get longer or shorter depending on amount of entities or size so not sure to what it would be related.