Well both of those cards are PCI-E 3 gen cards, but they should be compatible with a PCI-E mobo, but using a 1660 with any CPU compatible with that mobo would result in a huge bottleneck.
A 660 would work fine, but I would suggest upgrading the whole PC if possible since even a GTX 660 is barely able to play the modern games. But if you're fine with playing older games then a 660 should work fine.