If the graphics are using intrinsic VB6 commands which could be handed over to Direct2D or similar then they might benefit from GPU optimisation but I am not aware there is anything specific to TwinBasic that will bring the benefit of shifting from CPU to GPU, Faf. might have better understanding.

That might be something you can address now with VB6, that may carry over well to TB.

Multi-threading is not something anyone with VB6 experience will have much knowledge of. TheTrick and a few select others might be spawning off processes to carry out distinct tasks but multi-threading is a lot more than that. We'll have to see how TB handles it all and then see some examples from the clever chaps here on this forum.