So I've had Minecraft with Technic Launcher on my computer for a while now, it's always worked just fine, I've had to keep it on the minimal graphics (Smooth lighting off, Normal Render Distance, sometimes Short and even Tiny, Minimal Particles, Max FPS), and it's worked fine, but for no reason whatsoever, Minecraft had just started lagging horribly for no reason to point where I can't even play it anymore, even when not playing online!
Also, I haven't got the latest Technic Launcher, and I want to see if updating it will fix the problem, but before I get it, I need to know if my old saves will be compatible with it, and also if it's still possible to install custom packs the same way. Otherwise, I want to see if it's possible to fix it without updating it.
Oh, and my graphics card is an Intel Core i3.