To find out which texture formats to use in my next mobile game I performed raw texturing tests with the latest PowerVR GPUs (series 6).
I came to the conclusion that the support of ETC2/EAC textures (required in OpenGL ES 3.x) is somehow limited
PVRTC textures perform much better. I tested only 4bit vs 4bit per pixel formats. Could it be that ETC2 textures are uncompressed in the GPUs texture caches or have other limitations along the way?