Sony has gone full force with its 1080p machine guns since the PS4 came out. In a way, 1080p has become a moniker synonymous with "MORE POWA!" However, what has been documented as the greatest demonstration of the PS4's "supercharged" hardware didn't follow the Sony supported standard. More importantly, it had a good reason not to.
In a post by Eurogamer, it has been confirmed that Killzone: Shadow Fall's multiplayer has a 960 x 1080 frame buffer (in comparison, Titanfall's beta ran at 1408 x 792) , versus the 1080p 30 FPS delivery of the game's single-player. That's actually closer to 720p than 900p with a total of 1,036,800 pixels rendered per image versus the 2 million that 1080p is able to achieve.
This number conflicts with Sony's marketing which touted Killzone: Shadow Fall as a 1080p 60 FPS monster. Even the back of the box only says 1080p (as seen below).
NOTE: Killzone: Shadow Fall outputs at 1080p in single-player and multiplayer, but it isn't native. It uses a unique processing method that blends 960 x 1080 images together. Therefore, the 1080p advertised on the box isn't inaccurate. Sony's imprecise marketing is still valid, though.
So why in the world would Guerrilla Games offer a different resolution in the single-player and multiplayer environments? The answer is simple: frame rate. Having a frame rate as close to 60 as possible is incredibly important for a fluid online experience, particularly for shooters like Killzone. Guerrilla Games made the decision to drop the resolution in multiplayer to nearly half of its single-player campaign counterpart in order to push FPS beyond the 30 mark. The results speak for themselves.
Virtually nobody made a fuss about the graphics in Killzone: Shadow Fall's multiplayer, mostly because it still looked darn good. As I argued in my recent editorial, a game doesn't need to be 1080p to look good. Battlefield 4 and the Xbox One's Ryse: Son of Rome are some of the best games we've ever seen and they were 900p.
Now, Guerrilla Games wasn't able to achieve a locked frame rate of 60, but it got close; the game averages around 50 FPS. Gamers noticed the difference almost immediately, calling Killzone: Shadow Fall by far the smoothest Killzone to date, and reasonably so. Its predecessors never got close to 50 FPS.
To be fair, Killzone: Shadow Fall was a launch game. Even then it looked absolutely gorgeous, especially in single-player. It's not that the PS4 isn't capable of displaying jaw-dropping games at 1080p, it's that there are sometimes compromises to be made, and in this case there was a deadline to meet. In my opinion, smooth gameplay is an utmost priority, so any developer who chooses to not adhere to Sony's 1080p standard has my support.
The question that remains is what resolution future titles will run at. Naughty Dog is arguably the king of optimizing for console hardware. Will Uncharted 4 be 1080p? Sony hopes so.