parallell ATA is the older standard for connecting hard drives, optical drives, and a few other things. Serial ATA is the newer standard that allows for faster data transfer over a much smaller cable. It's also hot swappable from what I recall. you want Serial ATA... it's your friend. Someone who has more time and energy is welcome to elaborate further. IF you see someone say ATA-133, IDE, or EIDE, they are talking about Parallell ATA. Unless you see an "S" in front of the ATA, it ain't the new fandangled technology.