A data processing device includes processing circuitry 20 for executing a first memory access instruction to a first address of a memory device 40 and a second memory access instruction to a second address of the memory device 40, the first address being different from the second address. The data processing device also includes prefetching circuitry 30 for prefetching data from the memory device 40 based on a stride length 70 and instruction analysis circuitry 50 for determining a difference between the first address and the second address. Stride refining circuitry 60 is also provided to refine the stride length based on factors of the stride length and factors of the difference calculated by the instruction analysis circuitry 50.