Running Apache? If so, what is your server setup?
 

Just trying to see what people are currently running and what seems to get them the best performance.

vBulletin version: 4.2.3
PHP Version: 5.6.29
Apache version: 2.4
Apache handler: fcgi
PHP Caching: xcache
MySQL/MariaDB & version: MariaDB 10.1.21

Any specific tweaks or mods for vB or your server that you use for speed:
Nothing that seems to do very much for me. Looking forward to trying vB 4.2.5 with support for PHP 7.0/7.1 once it comes out of beta. I know I'll need to move from xcache to probably APCu for caching, should I still stick with fcgi as the handler?

(Copy and paste to share your setup.)

Atm ;

vBulletin version: 3.8.10
PHP Version: 5.6.30
Apache version: 2.2.15
Apache handler: apache2handler
PHP Caching: xcache
MySQL version: 5.5.54

Moving to soon ;

vBulletin version: 3.8.11
PHP Version: 7.0.16
Apache version: 2.2.15
Apache handler: apache2handler
PHP Caching: opcache
MySQL version: 5.5.54

I'm running my vBulletin 4.2.3 forum on the latest nginx/PHP (7.1.2 I think)/MariaDB version.

vBulletin version: 4.2.3
PHP Version: 5.6.30
Apache version: 2.4.25
Apache handler: apache2handler
PHP Caching: OPcache
MySQL/MariaDB & version: MariaDB 10.1.21
Engintron Nginx reverse proxy - compiled with http2/alpn

Test board
vBulletin version: 4.2.5 beta 1
PHP Version: 7.0.16
Apache version: 2.4.25
Apache handler: fcgi
PHP Caching: OPcache & APCu
MySQL/MariaDB & version: MariaDB 10.1.21

Thanks for posting.

Did the change to PHP 7 on your test machine eliminate most of the benefits you were getting from Engintron Nginx? Have you tried Engintron Nginx with PHP 7?

Any particular reason you went with fcgi handler on PHP 7?

My test board is non ssl for now and so will not benefit from http2/alpn thus I have it excluded in Engintron. I will switch it to https in due course and test.

APCu...

I tried to run vB on php 7 and mariadb but there are two addons could not be compatible with php7 so I am going to fix them and have vB on a new dedicated server.

??

I run APCu just fine on apache2handler ...