System and method for performing multi-rank command scheduling in DDR SDRAM memory systems

A DRAM command scheduling algorithm is presented that is designed to alleviate various constraints imposed upon high performance, high datarate, short channel DDRx SDRAM memory systems. The algorithm amortizes the overhead costs of rank-switching time and schedules around the tFAW bank activation constraint. A multi-rank DDRx memory system is also presented having at least two ranks of memory each having a number of banks and at least one memory controller configured for performing the hardware-implemented step of DRAM command scheduling for row access commands and column access commands. The step of command scheduling includes decoupling the row access commands from the column access commands; alternatively scheduling the decoupled row access commands to different ranks of memory; and group scheduling the decoupled column access commands to each bank of the number of banks of a given rank of the different ranks of memory.