Keep in mind that there's an extra conversion step with PDF. When you update the page view using the DVI viewer, LyX writes out a temporary LaTeX file and runs LaTeX against that file. LaTeX produces a DVI file as output, which the viewer then shows. When you view in PDF, the same steps are done, after which a converter program has to convert the DVI to PDF. So the extra delay you perceive may not be due to the use of GSview -- it may be the conversion step,which must be done no matter what viewer you choose.
I understand your argument, Paul. However, I am using pdflatex, which - I think - does not produce any intermediate DVI file. Furthermore, if one updates (using LyX) the output PDF file and wait 5 minutes before going to view the file on GSview, the same delay is perceived.
Paul
