Skyrims "Creation Engine" was a little poo and didn't handle multi core systems that well plus it's from 2011 so I really hope they've optimized it.
None of Bethesda's engines have ever supported CPUs very well. On Fallout 3 you had to do a INI hack to run the game on two cores only, otherwise it would just crash all of the time.
I've no doubt that they may have done some work under the hood to the Creation engine, but as I said, looking at the screenshots (and putting down my rose tinted "Because it's Fallout 4" spectacles)?
This doesn't look any better than Skyrim.
But.
Let's not be too harsh eh? Skyrim was visually stunning in places. I remember making silly spitting noises when I first went through the snow lol. It was like I could get it in my mouth.
Again let me be frank here. Compared to something like Crysis Fallout 3 looked pretty bloody awful. But, and it's a frikkin HUGE but, at times it was absolutely and utterly breathtaking.
I took so many screenshots just standing on a patch of scorched grass with a cracked road underneath my feet and the sun shining through. It looked so miserably beautiful it took my breath away. And the view you got when you left the vault and realised that this game was soddingly massive?
There were loads of "whoah stop, let me just stand here and look around for a bit" moments in Fallout 3.
New Vegas had been ever so slightly tweaked and used (I reckon) a couple of the mods for Fallout 3 so looked slightly fresher and better. However, without this post becoming a filibuster, New Vegas was rather empty.
What I mean is, once you did all of the main quests and so on and so forth and went around looking for entertainment? there wasn't much to be had. Most of the buildings were just objects with no entrance nor quests or exploration to be had.
Mind you to be fair to Obsidian they didn't really get that much time to make the game, so that's why it feels more like a large DLC for Fallout 3 than a stand alone game.
Games like this are all about time. Quests take time to program. The longer you spend on the game the bigger you can make it, so I am hoping that they spent the entire 3-5 years (depending on who you believe) making nothing but pure content.
So to hell with the graphics tbh. I want hours !