Optifine is a mod that greatly expands the graphics customization options. It can also work to reduce framerate issues and generally speeds up the running of Minecraft, even with no tweaking of options.
Features (general overview)
Optifine contains more features than listed here. Check the official thread for more information and a full list of features.
- Numerous animations such as fire and water can be turned on or off. Even the rain animation can be deactivated.
- Support for HD textures - prettier than ever.
- Increased render distance range.
- Configurable Smooth Lighting
- Mipmaps - Visual effect which makes distant objects look better by smoothing the texture details
- Fixes grass blocks side texture to match surrounding grass terrain
- Better Snow
- Use random mob textures if available in the texture pack
- Natural Textures
- FPS control - set the target framerate
- Optifine allows you to zoom in cinematically by pressing the Ctrl key on your keyboard in game.