not using multicore and GPU (Tegra3) optimazation ?

[geigermuller]

It's been said before that the CPU doesn't make much of a difference. It is the gpu that truly matters. And right now, the latest mobile gpus like powerVr 554, Mali 600, tegra 4, etc may be good for playing mobile games, but they are nothing compared to proper pc gpus. In fact, even integrated graphics like the intel 4000 are much better than mobile gpus.

So the point is that the gpu is the limiting factor. Multi core threading isn't going to help that much. What would be useful is optimising the emulator so it requires less gpu power, and that is indeed the direction in which development is heading.