If you work with large drawings, you can improve performance by opening only the view and layer geometry that you want to work with.
If you work with large drawings, you can use the Partial Open option of the OPEN command to select which view and layer geometry (graphical objects only) that you want to work with in a drawing. For example, if you load geometry from the EXTENTS view and the SITE layer, everything on the SITE layer that falls within the Extents view is loaded into the drawing.
You can only edit what is loaded into the drawing file, but all the drawing's named objects are available in the partially open drawing. Named objects include layers, views, blocks, dimension styles, text styles, viewport configurations, layouts, UCSs, and linetypes.
By organizing large drawings into sectored views, you can load and edit only what you need. For example, if you work with a city plan and need to edit only the southeast sector (sector D3 in the illustration), you can load this drawing area by specifying the predefined view. If you need to edit only the city plot numbers, you can load just the geometry on this specific layer.
After a drawing is partially open, you can load additional geometry from a view, selected area, or layer into the drawing by using PARTIALOAD. The Partial Open option is available only for drawings in AutoCAD 2000 or later format.