[powertower]

"made Apache die a miserable fast death. It just could not keep up, I've had friends look over my config (datacenter techs, help people scale their stuff, porn mostly) and they said it looked fine."

Apache crashing under load is indicative of seriously bad MPM settings: specifically the # of processes / threads allowed to be used (and some other settings such as KeepAlive timeout, how php is being used, etc).

With a properly configured MPM, anything coming over the process / thread limit goes into a backlog queue which is 511 entries long. Anything over this just gets dropped.

To iterate, Apache does not crash under load (too many requests), it crashes due to too many processes / threads (an MPM setting) being used and sometimes due to leaking modules such as mod_python/ruby.