New Hosting - Init. Connect. & Download faster, but TTFB slower. Why?

[pmeenan]

memcached and APC cache are different beasts. APC should automatically improve the performance of your PHP code which should most directly impact the TTFB (and you should enable it).

Memcache can be used by various components to cache data but each component needs to know about it and how to use it. If v-bulletin supports caching to memcache then it would be a good idea to enable it and configure it in v-bulletin.

The other variable at play is going to be your database. Did you migrate the database when you switched VPS as well? I know a lot less about tuning those but for something like v-bulletin it is going to be important as it usually has to run a bunch of queries to generate the pages (and those will also go against the first byte times).