This is the die of a Realtek ALC655 AC’97 audio CODEC. This came off a P4 mainboard that burned out. Sulfuric acid was used to liberate this die, more about however, cost the black coatings at the top left and bottom right sides of the die are simply super-glue and the result of a sloppy mounting job by myself. Still no artifacts and a lot of metal on the surface. Some interesting features can be seen in the three successive 100x images with varying depth.