Quote from Jaga
Having tried all three over extensive periods now (Standard, Smooth, and Multi-Core), I have to admit that overall, the Standard version provides the smoothest and most stable game of all three.
Perhaps it is my rig, but Smooth gives no improvement at all when compared to Standard (in fact standard is much better). I additionally will get invisible textures/meshes on mobs or chests randomly when using Smooth.
Multi-core is (for me), a complete mess. In addition to the invisible textures/meshes from Smooth, it is the least stable. At one point I had to remove it and revert to Smooth to solve random crashing issues that happened around every 10 minutes. Other times it seemed to work fine, but with lower FPS and higher chunk loads. For reference, I run a i7-930 with 12gb on Win7 x64.
Hope the feedback helps. Optifine is a great package.
i have your same problem its sopposedly the "Graphics driver"
i do not beleive the person who told me this knew what he was talking about.