GTA 4 was, while beautiful, just an awful performing engine everywhere you went. The console performance sucked. The pc performance sucked. Even today there are still issues that prevent it from becoming gta 5 levels of smooth. On the other hand, gta 5 was a god damn masterpiece. Even one the xbox and ps3 it was smooth. I noticed right off the bat that there simply wasn't any performance dips. Even when big explosions happened. Even when your mission took you on the train and one view had you viewing the side of the train and the other had full on streaming landscapes behind the character, it still stayed 30fps!
I don't recall any performance hiccups in the pc release either. It ran very well and not surprisingly after it had a year to port to next gen and then another year just for the pc port.
If we looked at red dead redemption, Sure they did a lot in the game to bring down performance, but thankfully newer hardware just made things better. I'll admit that it isn't %100 like gta5 though, even with a banging pc it is difficult to find a flawless framerate in rd2. Adding FSR really helped with its 4k goals. Anyways, it is gta.. I won't even think about expectations until another 2 years.