If GZip is enabled in IIS is it only going to improve performance for ASP pages or can it be setup to compress PHP pages as well?
                
                A: 
                
                
              
            Yes, gzip just compresses the content being served to the browser i.e. html and images.
                  zodeus
                   2009-03-04 16:23:23
                
              
                +1 
                A: 
                
                
              PHP also has built in support for gzip compression. You can initialize it by calling
ob_start("ob_gzhandler");
or by activating the zlib.output_compression directive in php.ini.
                  Emil H
                   2009-03-04 16:30:45
                
              Does this option only work in Apache or IIS as well?
                  Keith Maurino
                   2009-03-04 17:43:49
                It's independent of webserver. All the processing is done "before" the webserver.
                  Emil H
                   2009-03-04 23:19:17