Cutout material in mobile platform

Hi,I have a question about the performance in mobile platform.

my charactor model(over 2000 vertexes) which has a skin mesh has two materials.
these materials share same texture, and one is a opaque material for body, then another is a cutout material for hair.

I want to know which can improve performance, one mesh that has two materials(opaque one and cutout one) or one mesh that has only cutout marterial.

Minimizing the amount of pixels you need to conditionally discard should be your priority. So, the easy answer is: use two materials. However, I would first question why you are using the same texture for both materials. If you don’t need an alpha channel for the opaque areas, don’t use an RGBA texture for it, so your textures compress with maximized fidelity.