Byte swapping is not a particularly expensive operation. Pulling the data from RAM is the biggest delay in modern CPU, with a minor component related to the extra instructions. Since the instructions tend to get into the cache, the extra instructions don't detract significantly from the speed. Memory access dominates program execution speed for many if not most programs. We got this result while comparing execution speed for software with and without byte-swapping instructions while evaluating how to port some big-endian software to a little-endian processor.