Afterburner: Optimized

What it improves:

Rendering (FPS)

• Batched chunk drawing: each 128x64x128 block region is drawn with one call instead of one call per chunk section.
• Smaller chunk vertices: 16 bytes per vertex instead of 28, so the graphics card reads less for every block face. Chunks also take less graphics memory.
• Occlusion culling: chunks hidden behind nearer terrain (hills, caves, walls) aren't drawn. Works on OpenGL and Vulkan.
• Entity culling: mobs, chests, signs and other entities hidden behind terrain aren't drawn.
• Face culling: block faces that point away from the camera are skipped.
• Translucent face culling: the same for water, glass and ice.
• Faster draw prep: skips the per-frame work for chunk layers that have nothing to draw.
• Off-screen chunk building: chunks around you get built while the builders have time, not only once you look at them, so turning around shows fewer holes.
• Cheaper texture filtering: smooth filtering reads each texture 4 times per pixel instead of 8 or 9. The picture stays the same.

Memory

• Smaller chunk buffers: GPU memory for chunks grows as needed instead of being reserved 128 MB at a time. On laptops with built-in graphics, that memory is your normal RAM.
• Freed build copies: chunks let go of the copy of the blocks they were built from. Vanilla keeps one per chunk.
• Memory trim: while the game is paused or in the background, Java gives unused memory back to the system.

World and server

• Parallel world generation: trees, ores and structures are placed on every CPU core instead of one.
• Faster lighting: light updates remember the sections they're working in instead of looking them up for every block. It uses the same algorithm as vanilla, so the result is the same.
• Faster collisions: less work per block when checking what moving entities bump into.
• Faster mob AI: mob brains and searches for beds, job blocks and similar use plain arrays and loops instead of hash maps and streams.
• Leaner chunk sections: less memory for every block and biome container.

Other

• Lower worker priority: background workers run just below normal priority, so frames come first when every core is busy.