An electronic system includes: a processor configured to access operation data; a local cache memory, coupled to the processor, configured to store a limited amount of the operation data; a memory controller, coupled to the local cache memory, configured to maintain a flow of the operation data; and a memory subsystem, coupled to the memory controller, including: a first tier memory configured to store the operation data, with critical timing, by a fast control bus, and a second tier memory configured to store the operation data with non-critical timing, by a reduced performance control bus.