Memory Initialization Time Reduction

A method and apparatus to improve memory initialization in a memory of a computer system. Memory units in the memory comprise a plurality of ranks, each rank having a unique rank select. A parity generator outputs a parity bit corresponding to whether an encoded rank select has an even or odd number of "1"s. The parity bit is used by an Error Checking and Correcting (ECC) unit that generates ECC bits that are stored in a rank having an active rank select. During a first interval in a memory initialization period, ranks having an even number of "1"s in their encoded rank select are initialized in parallel. During a second interval in the memory initialization period, ranks having an odd number of "1"s in their encoded rank select are initialized in parallel.