Comment by NelsonMinar

I still do a fair amount of CGI; it's just fine for low traffic simple web services. Startup time for the script isn't awesome, to fix that you want FCGI or SCGI or whatever. Apache's default MPM these days is event (or worker) which scales CGI pretty well. Beware that it's not thread safe, so if your CGI script is doing something multithreaded it will break. (Related: if you're doing something multithreaded, it's time to graduate from CGI).