Controlling access to memory includes receiving a plurality of memory access requests and assigning corresponding time values to each. The assigned time values are adjusted based upon a clock pulse and a priority access list is generated. Factors consider include missed access deadlines, closeness to missing access deadlines, and whether a page is open. The highest ranked client is then passed to a sequencer to allow the requested access. Time values may be assigned and adjusted according to client ID or client type (latency or bandwidth). A plurality of power modes of operation are defined wherein operation in a selected power mode of operation is based at least in part on the assigned or adjusted time values. The processing is performed in hardware in parallel (at the same time) by associated logic circuits.