It is common to have the same texture rendered close the camera and at the same time far away (I.E for grass cutout cards in field of grass).
Would textures without mipmapping be noticeably more performant in this situation?
Also I have often wondered if I should be forcing a lower mip bias (within the material) when when i re-use high resolution textures in situations where i dont need much resolution (IE when using AO and Bump maps as masks for vertex paint texturing)
Mip maps increase performance since the GPU has to sample less texels for rendering a pixel, and it also increases cache locality (smaller mip map in memory -> higher cache hit rate).