i racke dmy brains but this is all i could come up with
Performance is slow when you are working with certain drawings. For example, performance with one 15 MB drawing file can be slow, while performance with a different 15-MB drawings is much faster.
Solution
Following are some of the causes of slow drawing performance.
The linetype scale factor (LTSCALE) is set too low. As a result, you have to draw very small linetype segments (they can appear "continuous" due to their small size.)
Postscript or TrueType fonts, or other fonts that are slow to generate, are used in the drawing.
The drawing limits are set small and the drawing includes objects with large coordinates beyond the limits or way out in space.
The drawing contains overly dense hatch patterns.
The drawing contains too much detail because it contains vertex-rich polylines. Reducing the number of vertices can sometimes increase drawing speed.
The drawing is not a true AutoCAD drawing. Drawing files that are translated from other programs can often display peculiar effects, including slowness. Wblock the drawing to rewrite the database in AutoCAD format and possibly increase the performance.
OLE objects are pasted into the drawing.