Speed/Performance

We're running some speed trials right now, and seeing that .php files are taking considerably longer even if they have NO <?php ?> tags. They're static pages, but by having the extension they're running slower do to the parser running through them. Does anyone have any "performance" tips for PHP files? Caches that aren't turned on by default? Here are the ones I know: Compile into Apache, not as a DSO Lots O RAM Don't use "known php extensions" for non-php files. We're taking a single-CPU client running a multithreaded app. It spawns X threads each of which open a socket, requests a file, and shuts down the socket. At 100 threads we're choking the server (K6 233) and not even touching the client's CPU usage. We're also deep into VM/swap space, even at 192 MB RAM. This is quite obviously not our production server (cringe at the thought). We're just "playing" with this one. Any one have more ideas? 2.4 kernel with khttpd? Won't affect PHP, but could make static pages faster... TIA -Szii