Hey mate,
Have you tried to check how much memory you have allocated for your Minecraft? If you're on Technic Launcher which I would suggest using if you're not doing so yet you can open it and click on Launcher Options which is at the right-top when you open it. From there you can allocate more RAM to your minecraft, do keep in mind to check how much RAM you have in total. I'm running 8gb and it works perfectly, I've heard people doing 4gb and still run it fairly smooth.
Hope this helps,