[webizen]

Originally Posted by Home Alone

I have XCache, Memcached and Litespeed Cache installed. I have VBSEO configured to use Memcached since it can't use XCache if it runs from the command line.

None of that helps. When the site is busy and there are 6 - 7000 people online the site lags and the load increases and it's always because of hundreds of vbseo.php processes.

The server has 24GB of RAM and and Quad Core E5620 processors.

Out of all the mods installed on the site, only VBSEO runs as an external application. Why?

It is PHP (not vbseo specifically) that is handled as external application.

please elaborate "none of that helps". do you mean none of them make any difference or help a bit but not enough? pls note that vbseo is extensive php application and consumes much cpu power. maybe your server is unable to keep up with the load as your site has more users.