Migrated to new, faster server - php script now running slower...

I migrated to a new server with 8 cores(from 4) and 12GB RAM (from 4GB). An important php script I am running now takes 6.5 hours to run up from under 2 hours. This is the script btw: http://www.xml-sitemaps.com/ - the standalone.

Ignoring thoughts about the script itself, moving to a faster one, different platform etc, what can I look into to diagnose this problem?

I’m not sure if this is an issue, but could php-cgi/mod_php/FastCGI be an issue? Why nearly 4X as long to process on a much faster server?

Also, what are the differences among php-cgi/mod_php/FastCGI ? My server is completely private and all domains on it are my own and not shared with others, so I have zero security concerns regarding other users. Thoughts on which to use? How to implement?

Thank you.

It seems none of my site migrated the way they were running previously(mod_php) and were set up to run under PHP-CGI (CGI wrapper) so my PHP caching app was not working properly(eAccelerator). I manually edited httpd.conf to make them run as mod_php and eaccelerator works now.

See my other post for what lines to remove to do this, though I am not even 100% sure if it was ok to do so, but pretty sure…