Or put a nginx in front of the Apache, disable keepalives in the Apache server (letting nginx deal with keepalive from the clients), and reduce MaxClients so ev

Or put a nginx in front of the Apache, disable keepalives in the Apache server (letting nginx deal with keepalive from the clients), and reduce MaxClients so even if they're all active the server does not go into swap. (I've done exactly that for a friend, it made a huge difference in how much traffic his box can handle).