How much faster is it?
The speed increase is similar to Mod_Perl.

How does it work?
Each cgi script is modified to include a few new lines at the top. When the cgi script is run the first time, everything is handled normally but when it is done, the script doesn't exit, instead it sticks around waiting for another request, like a mini-server.

What are the advantages of FastCGI?
- Speed.
- A small decrease in memory use on busy sites since there is no need to compile for each request.
- Ability to choose only certain scripts for the speed increase unlike Mod_Perl where all scripts in a directory are affected.
- Works with web servers other than Apache (but Apache runs most web servers anyway).

What are the disadvantages of FastCGI?
- Increased memory usage on less-busy sites since compiled script stays stored in memory when it might not be needed again soon.
- Always requires recompiling Apache to install.
- Installation instructions are geared toward experienced Unix administrators.
- All library files are in memory for each script running FastCGI, which uses a lot of extra memory.
- All scripts must be edited to include FastCGI code. This needs to be after all upgrades.
- Unlike Mod_Perl, we do not provide support for FastCGI related problems.