Unlike bacteria, archaea cell walls do not contain peptidoglycan.
Archaea have different membrane lipid bonding compared to Bacteria and Eucarya.
Archaea have different metabolic pathways.
Metabolic differences:
Archaea are very metabolically diverse, so they are hard to generalize.
Archaea do not use glycolysis pathway to break down glucose (though they do use similar pathways).
Many archaea do not have functional Kreb’s cycle pathways (but some do).