Go to options in the skyrim launcher and set shadows from ultra to high. Setting it to hight will give you a very large fps boost and will make your game more stable. Many people have confirmed this. Using ENB, enabling SSAO can diminish your performance depending on the SSAO quality setting. Try to lower the quality of it, if you are using SSAO or completely disable SSAO. If you also have stutter, you can try to use optimizer textures. This program will compress your textures, ergo reducing the HDD space they take, meaning less loading, less stutter.