 Though the Sega CD offers a faster processor , its main purpose is to expand the size of the games . Whereas ROM cartridges of the day typically contained 8 to 16 megabits of data , a CD @-@ ROM disc can hold more than 640 megabytes of data , or more than 320 times the storage of a Genesis cartridge . This allows the Sega CD to run games containing full motion video . 
