Which is Better GT 730 DDR3 2GB 128bit or GT 730 1GB 64 bit DDR5

The are pretty much exactly the same.

The issue is one of the cards is likely a different architecture/re-brand on a node shrink. The 'newer' version would likely be the best bet. You may likely check out the different versions on the TechPowerUp GPU database.

That said, neither is a very powerful card -- their competition is effectively the on-chip 'APU' hraphic engines.