The old texture code was being bottle necked by the texture reads. We mirrored the real3d texture memory directly, including the mipmaps in a single large texture. I *think* most h/w has some sort of texture cache for a 2x2 or 4x4 block of pixels for a texture. What we were doing was reading the base texture, then reading the mipmap data from a totally separate part of the same texture which I can only assume flushed this cache. What I did was to create mipmap chains for the texture sheet, then copy the mipmap data there. Doing this basically doubles performance.
