The way to speed up a web site is to first find out where/why it is slow, then address those issues. Just trying random "solutions" is like throwing darts in the general direction of a dartboard and hoping one of them hits the bullseye. Search for the various tools out there than can show you what is taking time on your specific web pages -- and if it includes delays on the server side, then you'll need server-side tools to determine where your application/database needs to be tweaked.
Measure first, then optimize based on those measurements. Locate the bullseye, then directly place your dart in it, rather than hoping.
