I just wanted to mention that all of the suggestions I’ve heard haven’t worked. Simply closing the editor and re-opening will often flush the memory, so I think it’s leading a lot of people to think that they found a solution when they didn’t.
I can confirm that the following fixes DO NOT WORK:
increasing system page file
adjusting engine VRAM % with PoolSizeVRAMPercentage=0
Switching to Direct X 11 or Vulcan