If you stream your VBO  i think it is held only in main memory (don't think OpenGL spec say that, so probably it is to drivers implementors). For devices wich have only 1 memory that should not be a problem causing heavy performance drop. anyway 2 copies are very usefull if you want to change data in the second copy with a thread, while with only 1 that's not possible. You can still hold 2 copies and stream a different copy every frame (depending on your needs)

If you stream your VBO  i think it is held only in main memory (don't think OpenGL spec say that, so probably it is to drivers implementors). For devices wich have only 1 memory that should not be a problem causing heavy performance drop. anyway 2 copies are very usefull if you want to change data in the second copy with a thread, while with only 1 that's not possible.

If you stream your VBO  i think it is held only in main memory (don't think OpenGL spec say that, so probably it is to drivers implementors). For devices wich have only 1 memory that should not be a problem causing heavy performance drop. anyway 2 copies are very usefull if you want to change data in the second copy with a thread, while with only 1 thread that's not possible.