Well I moved to the 4.13 cause I read the new LOD system in landscape shutdown the use of tessellation to just LOD0 but here looks like all works pretty bad, will try in 4.12 never tried in it.
The 4.13 takes me about 12,5GB of Ram only at edit looking at landscape and load or save the map file takes all the ram.
The other day in 4.13 too the meshes at import of size 350k of vertex take lots in load too not sure if is related with my computer or what is… but before worked better I think.