You might be surprised in some cases.... We recently did some tsung testing on an optimization system we've developed (purposely general here).<p>Running it the developers workstation w/ APC and Memcache and local Percona MySQL, it maxed at 300 request/s. (It's just a workstation, remember). Anyway, there may be some observer effects here, but the profiler indicated that most the time was being spent on php functions and system calls.<p>So we might be in the 1% you're describing. Or _maybe_ it's a more than 1% after all.