Unaligned memory access

The problem starts in the memory chip. Memory is capable to read certain number of bytes at a time. If you try to read from unaligned memory address, your request will cause RAM chip to do two read operations. For instance, assuming RAM works with units of 8 bytes, trying to read 8 bytes from relative offset of 5 will cause RAM chips to do two read operations. First will read bytes 0-7. Second will read bytes 8-15. As a result, the relatively slow memory access will become even slower.