php.ini variables of interest

short_open_tag = On (might be needed to run VBulletin)

--------Other interesting values------
auto_globals_jit boolean
auto_globals_jit = On (Could be good for performance)

When enabled, the SERVER and ENV variables are created when they're first used (Just In Time) instead of when the script starts. If these variables are not used within a script, having this directive on will result in a performance gain.

The PHP directives register_globals, register_long_arrays, and register_argc_argv must be disabled for this directive to have any affect.