If this is happening specifically to CSS files, it's possibly because you're using $this->getStyleSheet('reset.css') calls in your theme headers, which runs through some C5 processing to support stylesheet customizations via the dashboard. If you don't have or need these customizations, then you should use $this->getThemePath().'/reset.css' to reference the stylesheets in your header instead.

Otherwise you might have some luck with one of the minifier addons that are floating around the forums (MISER and Tinifier I think they're called).

Thanks Jordan. Unfortunately that's not the solution. Indeed there are other things that have exceptionally long load times likewise. For example, index.php is taking some clients forever (20-30 seconds) to load, while it flies for others. On Mac OS X I have seen no problems whatsoever on Firefox, Safari nor Chrome. Yet on Windows XP I've seen all of the same clients exhibit the same failing behavior.

Further, these clients are all on the same network and subnet as the server itself. It is as though there is no explanation at all for this. IRC is silent. No one seems to be able to chime in on any advice. Nothing is pointing towards the server itself having any issues at all as other php web apps are running without any issue whatsoever at the moment.