A multi-ring memory controller sends request packets to multiple rings of serial flash-memory chips. Each of the multiple rings has serial flash-memory chips with serial links in a uni-directional ring. Each serial flash-memory chip has a bypassing transceiver with a device ID checker that bypasses serial packets to a clock re-synchronizer and bypass logic for retransmission to the next device in the ring, or extracts the serial packet to the local device when an ID match occurs. Serial packets pass through all devices in the ring during one round-trip transaction from the controller. The average latency of one round is constant for all devices on the ring, reducing data-dependent performance, since the same packet latency occurs regardless of the data location on the ring. The serial links can be a Peripheral Component Interconnect (PCI) Express bus. Packets have modified-PCI-Express headers that define the packet type and data-payload length.