The main reason for those game very poor performance is mainly that they rolled out their own 3d engine. Having programmed several 3d engine, I can say it's re

The main reason for those game very poor performance is mainly that they rolled out their own 3d engine. Having programmed several 3d engine, I can say it's really simple to program a 3d engine but it's really hard and time consuming to program one that has reasonnable performance. Minecraft was especially bad because it used very old version of OpenGL (the 1.5 - 2.0 OpenGL with fixed pipeline) which is really not adapted to modern GPU.