A computing system includes: an instruction dispatch module configured to receive an address stream; a prefetch module, coupled to the instruction dispatch module, configured to: train to concurrently detect a single-stride pattern or a multi-stride pattern from the address stream, speculatively fetch a program data based on the single-stride pattern or the multi-stride pattern, and continue to train for the single-stride pattern with a larger value for a stride count or for the multi-stride pattern.