I currently use the Sphax FTB pack, and I love it! I use the 64x64 pack, however, because 128 is just unusable for me. I spit out well over 100 frames with the 64x, but as soon as I change to 128, even if i switch all the settings to minimum, my framerate fluctuates between about 8 and 25. Opening GUIs takes much longer, and everything incredibly choppy. I have all the optimizations installed, and I believe I've done everything right with the texture packs (I've reinstalled each about 3 times). Is there any source of this massive lag, and any way to fix it?