Leehams

My laptop runs any mod in the technic pack at very low fps. When looking at mobs, I dip to 6 ish FPS. I have tried changing how much RAM the technic pack is to use, but in task manager, the amount of physical memory the game is taking up is not as high as I selected ( I selected 4 GB, it uses 1.2 MG). Also, I have a quad core i7 sandy bridge CPS, but the vast majority of the processing load is concentrated on one core. I have tried changing all the in-game settings, but nothing helps. Any suggestions would be appreciated!