Upgrade to 4.2.5 Pages Run Really Slow

[XGC Viper XI]

After upgrading to 4.2.5 the site has been running really slow www.xiledgaming.com. Had to upgrade to php 5.6 and had to deal with numerous database issues. The host increased the memory but that doesn't make sense as the site ran perfectly before the upgrade. What can be the issue? Host says its due to too many usergroups, but they was their before the upgrade. If there is no solution, how can I downgrade back to the previous version of vBulletin?

Thanks,
Viper

[Mark.B]

The only way to downgrade is to restore from a backup taken from before the upgrade.

There is nothing in 4.2.5 that would cause this.
You could try upgrading to php 7.1, this brings considerable performance improvements.

[XGC Viper XI]

Thanks for your response. Could numerous amount of usergroups (a few hundred) be a part of the problem? I can change the php to 7, but will that affect the mods from vBulletin.org from working properly? If so, will that one setting in the options the PHP Compatibility if set will that help?
Thanks,
Viper