How to shorten the wait period between clicking on thread and page changing?

[Dave]

You would probably not notice any difference with a more powerful server, unless you order a server which is closer to your own location. But in that case only you and people who live around your area will notice a small difference (probably maximum 50-100ms).

Like I said in my previous post my waiting time is about 600ms to 750ms which is about average for vBulletin forums. You could look into changing to MariaDB instead of MySQL and using nginx instead of Apache and configuring a cache server such as memcached which vBulletin supports.

This all might give you a little boost.