For the last few days I have worked on my first OpenGL test project. It's a simple voxel engine in Java with the LWJGL library. I used chunks, just like Minecraft. Those chunks are 16*16*128. When I load the world, I loop over all the blocks in a chunk, creating a VBO with the coordinates, normal coordinates and texture coordinates of every single chunk. Now, when I render 1 chunk of 16*16*128, I get around 250 FPS (Yes, this renders actually all the cubes inside the chunk so 16*16*128 = 32768 quads). However, when I try to render 4 chunks, it already dropped to 40 FPS. What would be the best way to increase my FPS?