The total amount of Texture memory that Unity would use if it loads all Textures at mipmap level 0. This is a theoretical value that does not take into account any input from the streaming system or any other input, for example when you set the Texture2D.requestedMipmapLevel manually. To see a Texture memory value that takes inputs into account, use desiredTextureMemory. totalTextureMemory only includes instances of Texture2D and CubeMap Textures. This value does not include any other Texture types, or 2D and CubeMap Textures that Unity creates internally.

public static ulong totalTextureMemory { get; }