-To say in short DVD kicks butt. The spin speeds of them are not in comparison to the newer CD-ROM's but the data held on one disk is incredible. Expect to see as much as 17GB a disk. No joke, of course this will use both sides of the DVD and dual layering of information. Even single sided DVD can hold as much as 4 GB. In comparison to the CD-ROM we are looking at 650 MB a disk. This isn't much compared the what the DVD can hold. Now if they could just make them faster then we could eliminate the hard drive.. haha. Maybe not. Well what makes this little invention tick? Lets try and figure it out a little. Its kinda neat.