Memory access efficiency for packet applications may be improved by transferring full partitions of data. The number of full partitions written to external memory may be increased by temporarily storing packets using on-chip memory that is on a chip with the processor. Before writing packets to external memory, packets of length smaller than the external memory partition size may be temporarily stored in the on-chip memory until an amount corresponding to a full or nearly full partition has been collected, at which point the data can be efficiently written to an external memory partition.