Another Virtual Memory Issue.
  Part of the efficiency of the VM model is based on working with 
    standard sized pages.

  However, 
    Even if program or data does not take up all bytes of a frame,
    All bytes are reserved for specific page.

  If many small blocks of data, 
    Much space is wasted. 
 
  This is known as internal fragmentation.

  Since most programs and blocks of data span several virtual pages,
    The percentage of partial frames tend to be small.

  Alternative is to use segmentation.