UE4 4.10 editor still causes this issue here. Usually it is not crashing but the editor eats up to 6 GB ram… a few seconds later 12 GB ram … drops down quick to 700 MB … 1.8 GB and back to 6 GB is writing the hole time something on the HD with about 9MB/s. I’ve no clue what happens here as the game is not running in this time and the hole project folder on the HD is way slimmer (about 2.7 GB). But probably that writing of the UE4 process (that should be idle in the editor in that time) is a clue regarding some auto-save. If I restart the project it’s pretty stable consuming 1GB ram (at least for a while).