the size and amount of textures doesn't really effect performance. the amount of materials and the amount of batches/draw calls that will result out of them does ... the fewer draw calls the better ! so try to use as few materials as you possibly can without fucking up your own work flow too much.
but very often amount of materials is related to amount of textures. (unless the engine internally optimizes for texture atlas useage to create bigger batches). in a regular engine you will get an extra draw call for every new texture you use. (not as in texture combinations diffuse/spec... for a material, but say your…
[ QUOTE ] the size and amount of textures doesn't really effect performance. [/ QUOTE ] Up until the scene requests reads from a texture set that doesn't fit in vram, in which case you will fall off a performance cliff. Considering vram varies from 768 Mb down to 128 or lower, texture memory use is definitely an issue.