Sometimes working with large, complex drawings may require large amounts of video memory. So when your currently opened drawings exceeded the allocated memory limit, the high quality geometry option is turned off and you will see a reduction in the quality of the displayed objects in the drawings.
Note: Only a portion of the total video memory is allocated to high quality geometry setting to maintain stability of the system.
The reduced graphics quality is temporary. Close all drawings and restart AutoCAD to restore the high quality graphics.
To stop the error message from displaying while working on a drawing, do the following:
At the right end of the status bar, right-click Graphics Performance ( Find).
In the Graphics Performance dialog box, under Effects Settings, 2D Display Settings drop-down list, select Basic Mode or Intermediate Mode.
Click OK.
Note: If the Graphics Performance button is not displayed on the status bar, click Customization ( Find), the right-most button on the status bar and then choose Graphics Performance.