Various embodiments for reducing external bandwidth requirements for transferring graphics data are included. One embodiment includes a system for reducing the external bandwidth requirements for transferring graphics data comprising a prediction error calculator configured to generate a prediction error matrix for a pixel tile of z-coordinate data, a bit length calculator configured to calculate the number of bits needed to store the prediction error matrix, a data encoder configured to encode the prediction error matrix into a compressed block and a packer configured to shift the compressed block in a single operation to an external memory location.