Yup- that would make sense. If you have a chip that puts out 60W of heat, you need a 60W peltier on top to just break even- and then you don't really do anything. You have to cool 120W worth of heat. To really make a difference, you'd want to put a 100W or 150W peltier on top, and then you'd have 160W or 210W to get rid of. Not fun on an air cooled heat sink.