Two settings can affect graphics performance. These are the "Allow Optimize Drawing" and "Cell Size Limit" options in Global Settings.
The "Allow Optimize Drawing" option allows for enabling/disabling the optimized drawing routine. This option can make rendering much faster for large datasets, and generally should be used. The drawing layers which display the TIN/grid as contoured areas/isohyets, Thiessen polygons, and the TIN mesh all employ optimized drawing. The contour/isohyet layer is the most CPU intensive layer to compute and draw, especially when contour smoothing is enabled. When displaying the contour layer for a map window, if the TIN represents a gridded dataset, the width and height of screen pixels that an individual grid cell occupies is computed. This value is compared to the 'Cell Size Limit'. If the number of pixels is less than the limit, the layer is drawn by drawing small rectangular blocks of color instead of attempting to contour the cell. Each time a map view is computed the program makes this computation so as an image is zoomed in or out it will automatically select the correct draw technique for the area being displayed. The TIN mesh and the Thiessen polygon layer work in a similar manner. Under certain situations, this rendering strategy may cause rendering abnormalities. If rendering abnormalities are observed, the option should be disabled.
The "Cell Size Limit" specifies the upper limit on the number of pixels in the Map Window that can be represented by a grid cell. Once the ratio of pixels per grid cell falls below this the program reverts to normal drawing methods. A larger number means that images draw more efficiently but the resultant images begin to appear 'pixelated' if the number is too large. The default value for this is 2. Increasing this value will lead to faster rendering, but decreased quality of the images.