my customer is getting ready to go live and during final testing has noticed a very serious performance issue. their configuration is a web server running eCM, an application server and a database server, all in house. during analysis they noticed that every page brings in a ton of style sheets. they feel this is contributing to the preformance issue. is there a way to eliminate the unused style sheets and will this improve performance? are there other issues they should be looking at to improve performance?
2 Things:
How do you know, did you actually profile how long each piece of the page took to come down? If not use fiddler (http://www.fiddlertool.com/fiddler/) or another appropriate performance tool of your choice. I suspect the CSS pages are only a small part of the performance picture. I also suspect performance of some SQL queries is probably more of your problem. Finding and fixing them using the ColdFusion debugger, would probably yield greater dividends than messing with style sheets.
That said, some IIS changes will help speed things up a bit. I have noticed on many websites that people set up is they do not properly configure IIS. Turning on IIS compression (HTTP compression) can be a big performance boost. Also, make sure you configured IIS to send your static files (css, images, js) with a cached until header. This will prevent web browsers from re requesting the same CSS page over and over, during a session. This will lower overhead a bit too, however, it will not be drastic, since most web browsers will not rerequest the file, they will simply say, give me the file if it has changed since last time you sent me it.