Penello on X1 vs PS4: "Developers are confirming cross platform games are running the same on both platforms":

[JEMC]

fallen said:

In the past Penello has said more like "differnce wont be that big", but here he's saying developers are telling him they are equal.

That's not what they are saying.

Devs are saying that GAMES run the same on both consoles, which is kind of expected given that it's the first batch of games and that most studios are working with game engines not optimized to work for either console.

The differences in power, if there are any, will start to become more noticeable once devs get used with the consoles and the engines are tweaked to take advantage of each console's strengths.