Editor grinds to a crawl editing a streaming map

I am experiencing unreliability of the Unreal Editor in version 4.10.4 while attempting to edit a fairly large map comprised of lightweight streaming tiles. The editor grinds to a crawl, and the memory consumption is up to 19 gigabytes.

1st problem is importing a mass of landscape tiles into a new level, there are 1600 tiles (40 x 40). The tiles themselves only have a terrain size of 505, and no textures are imported during tile import. The editor starts of really fast, importing almost 40 tiles per second, but it starts to slow down. Now its about 3/4 of the way through, the tile import is now taking over a minute per tile, and the memory consumption has grown to 19gb on the editor.

I have noticed that for no reason at all when editing any blue prints while a streaming level is loaded, or editing a streaming map by painting textures on to the landscape, the editor will start off on a reasonable amount of memory and be really quick to respond to commands, but for no reason at all, memory consumption will ramp up to between 16gb to 24gb and that is when the editor becomes virtually unresponsive when saving tiles, editing blueprints, or unloading tiles or painting on to the landscape. It doesn’t seem to be related to the number of tiles as I have similar issues when editing smaller maps.

I’m confused when you come to the Landscape, you’re saying you have a single Landscape, which is 40 * 40 Components? Or do you have 1,600 Landscape chunks which are 40 * 40 tiles each? If it’s the latter, then I’m amazed it doesn’t crash earlier…

Its a streaming level with world composition enabled and I have 40 x 40 terrain tiles at 505 x 505 resolution. It took 7 hours to import into the editor and the editor peaked at 24gb ram.

If I’m picturing it right then that sounds about right to me then to be honest, Kite Demo has similar requirements.

Even though Kite Demo has similar requirements, there is still a huge memory leak in the editor, this can be replicated by loading and unloading tiles. If I load up my big map, I can see all the tiles in the levels window, and they are all unloaded. Memory usage of the editor is 1.1gb. Then if I simply scroll around the world composition window and load a few tiles, and then unload them, the memory will keep growing until its using 20gb. I would understand the memory usage if I tried loading all the tiles at the same time, since the Kite Demo is stated to need 24gb if you try and load the whole map at once, but I’m not loading the whole thing, only a few tiles and then unloading and still the memory keeps growing!