Forum very slow when loggined in
 

Hello,

I have got a very rare problem:

My forum is very fast when i'm as guest but when i log in the forum starts to be very slow, more than 10 seconds on reply for a page.

I tested everything on the server side but nothing, all are okay and how i said when i'm visiting the forum as a guest the forums works perfectly.

I tested disabling all plugins (Disable hooks by config.php) also tested with other style on my forum for see if there are any problem with it and nothing.

It is a very odd issue :(

I tested it under other users not only my admin user and always is the same, others web browsers even other computers and always the same problem.

Others vBulletin in the same server works good.

I run vBulletin 3.8.3 and i have near 1.5 million of registered users.

Thanks in advance.