^ agreed for wattage
Some SATA CD-ROMs should just draw on the 5V line, but most (especially burners) will draw from the 12v line as well.
I've heard rumor that some superslimline/green style devices will draw from the 3v, but I've never seen them.
This is a good reference, but not 100% applicablehttp://www.allpinouts.org/index.php/Serial_ATA_(SATA,_Serial_Advanced_Technology_Attachment)
we need to know exactly which CDROM device you're investigating...