If it is not obvious why a Postscript or PDF file is big, try viewing a Postscript version of the file it with a Postscript viewer (such as Ghostscript or Ghostview). As the file is displayed, you will see which parts take a long time to draw: these are the likely source of the problem.
If the image is built up from many small points that overlay each other, as is common in output from tracking programs, the file can take an extremely long time to display. Since the final image is the result of overlaying all of these small images, a perfectly acceptable result can be obtained by converting the figure to a bitmap image. See Graphics: Working with Large Files.
As with extremely large files, files that won't print are often caused by graphics, and it can be helpful to the view a Postscript version of the file with a viewer, as mentioned previously. See Graphics: Working with Large Files
Recreating your Postscript or PDF with a different Postscript printer driver or with other printer options might also resolve the problem. See JACoW Postscript Printer.