Both versions use an amorphous diamond infusion process. However, version 5 uses a different coating process which offers a purer form of amorphous diamond, or a higher percentage of diamond bonds (85% diamond bonds vs. version 4 having about 33% diamond bonds). Version 5's purity is such that it will show a diamond signature under Raman spectroscopy, whereas version 4 will not.
The main difference on an everyday basis is that version 5 has a slightly higher luster, of about 5% more than version 4 - it is thus a slight visual improvement.
