Is it possible for you to send your file to us?
use the uploader link in my signature and once you have uploaded your file. Let me know the file name.
Also, try to check if you have any hardware issues regarding RAM before sending in the file. Also, is your scene using a lot of displacement? Does turning off displacement from Render Setup>Common>Displacement fix the issue?
Looking forward to hearing back from you.
Regards,
Avi