I have an optimization problem. I'm using a look-up table to map a pixel in an image: for (uint32_t index = 0u; index < imgSize; index++) { img[ lt[ index ] ] = val; } Is there a faster way to do this, perhaps using a reinterpret_cast or something like that? I am accessing two different memory addresses, so what is the compiler doing? One solution is to do a set of reads to access adjacent memory addresses. struct mblock { uint32_t buf[10u]; }; mblock mb; for (uint32_t index = 0u; index < imgSize; index += 10u) { mb = *reinterpret_cast<mblock*>(lt + index)); for (uint8_t i = 0u; i < 10u; i ++) { mb.buf[i] += img; } for (uint8_t i = 0u; i < 10u; i ++) { *( mb.buf[i] ) = val; } } This speeds up the code because I'm separating the image access from the table look-up; the positions in the look-up table are adjacent. I still get the image access problem as it is accessing random address positions.