Two-dimensional arrays are generally arranged in memory in row-major order or column-major order. Sophisticated programmers, or occasionally sophisticated compilers, match the loop structure to the language's storage layout in order to maximise spatial locality. Unsophisticated programmers do not, and the performance loss is often dramatic -- up to a factor of 20. With knowledge of how the array will be used, it is often possible to choose between the two layouts in order to maximise spatial locality. In this paper we study the Morton storage layout, which has substantial spatial locality whether traversed in row-major or column-major order. We present results from a suite of simple application kernels which show that, on the AMD Athlon and Pentium III, for arrays larger than 256 Ã256, Morton array layout, even implemented with a lookup table with no compiler support, is always within 61% of both row-major and column-major -- and is sometimes faster.