Even the menu lags!

[tantalus227]

I'm running a Windows 10 laptop with 8gb RAM (3gb allocated in Technic Launcher). I can play everything perfectly fine except Hexxit. It'll load up but the menu screen is massively slow... even the background image moves slowly! This isn't something I've come across before so I'm struggling to find the cause or solution. If I manage to get into a game the massive lag continues and the game is unplayable.

I've no idea what is going on, I've tried allocating more RAM and the like but nothing I've tried is working. Nothing like this has happened with any other modpacks I've played.

 

Anyone got any ideas? I really want to get onto a server and play!