Lvds Vs Ddr

What's your SERDES rate? If it's /1 or /2, then the altlvds megafunction will build it's logic out of the altddio primitives, and it's essentially the same thing. If it's a larger factor, say /4, then the dedicated LVDS logic is used. It will have better timing margins and dedicated for LVDS. (From a power point of view, I'm guessing it should be lower power, but probably not in a measurable manner. They're both using dedicated structures in the silicon, and should be insignificant in the grand scheme of things.)