[mike243]

A dedicated freezer has the same temps a refridge/freezer has so time will be the same on both, a freezer without a defrost system say a chest freezer the food will last longer due to no defrost cycle to put heat into the cabinet other than you opening the door. a upright freezer that has the cooling coils made into the shelfs are better than a frost free for long term storage but the chest freezer is the best. The reason is when you open the chest freezer door the cold air doesn't fall out like a upright unit. I work on refridge and freezers for a living and know just a little bit about them.