I have a contour feature class that takes up 2 GB in a File GDB. When I move it to SDE the disk space quadrupled. This is a SQL Server instance of SDE. I've tried a number of different methods. I have the same problem regardless if I use ArcGIS 10.5.1 or PRO. I've tried SQL spatial and ESRI binary types for the destination feature class. To move the data I've tried; Load Features, Append, Copy Features, and an old fashion copy/paste. I keep getting the same result, a huge 'file' that takes forever to render. I can move the data between File GDBs with no problem. Any ideas?