Very Slow Page Load - ASP/PHP CSS file latency

I've searched for this, but can't find anything - maybe I'm describing it badly!?

Anyway - I have a website (on an IIS 6 server) whose pages loads 2 or 3 CSS开发者_如何学JAVA files, these css files are actually ASP files with the response headers set accordingly.

The ASP in the files simply reads the query string to set colours of various css rules based on user preferences.

I've noticed that sometimes pages are loading very slowly, and using the dev tools in Chrome (although this seems to apply in all browsers) I could see the page load is stalling on these CSS files, the reported latency can be up to 2 minutes - everything else only takes a few milliseconds.

I've tried using PHP files instead of ASP files, but this makes no difference!

The website is behind password so I can't really demo it easily - although could try and set something up if it would help - Although it isn't consistent, it seem to happen most of the time, but sometimes can be quite fast!

Any ideas what I could try?

Thanks

A couple of things you can try are using Google's page speed or Yahoo's YSlow - both will generate suggestions for you to help improve performance.