When is 60fps not truly 60fps? That's the question we asked ourselves as we played through the PS4 and Xbox One renditions of Diablo 3 - a game that targets that tip-top number but with bizarre consequences owing to the unusual rendering set-up of Blizzard's in-house engine.
To cut to the chase, the PS4 version isn't as smooth in action as its Xbox One counterpart, despite both versions sharing identical assets to PC on its highest settings. Having tested both extensively over the last few days, with a mind to produce a full Face-Off feature once the Gamescom mania is dispensed with, the promise of 60fps is, on the face of it, delivered on both of the new-wave consoles. We ran both versions of the game through our analysis tools, which reported a flawless frame-rate on both - but there's a catch.
Unique to Diablo 3 is its method of producing frames, where character animations, alpha effects and its lighting model are rendered independently of camera movement. As you can see in our video below, actual gameplay can stutter down to near the 40fps line on PS4, while the camera continues to pan across the environment at a clean 60fps. It's difficult to ascertain exactly why the game presents itself like this, but it may well be the case that Blizzard has adopted a rendering strategy that ensures a 60fps refresh regardless, while some important elements of the scene to be updated at varying intervals. If so, it's an interesting technique that doesn't quite pan out.
Our test is running the full, disc-based UK versions of each game, on the most up-to-date patch available at the time of writing. Specifically, the PS4 runs at full 1080p as promised, with patch version C126.96.36.19991 instated on the menu screen, while the Xbox One renders at a lesser 900p resolution with the C188.8.131.5214 build in effect. Of course, we're promised a day-one update to 1080p on Microsoft's platform, with Blizzard seeing an opportunity in the June SDK to optimise further.
Based on our video analysis, each game renders out a perfect 60 frames per second - but in analysing the all-crucial gameplay, we see frame-rates on both platforms running with different practical results. Based on our initial playthrough, the worst of it occurs at the very start on PS4; around the gates of the New Tristram hub area. Characters and projectile arrows can run at essentially half their frame-rates as skeletons rise from the perimeter. Despite repeated tests, the Xbox One version only produces occasional hiccups in matching scenes.
Sounds like the PS4's resolution advantage is undermined (and will be nullified when the Xbox One patch hits anyway), with the framerate not being up to par with the Xbox One version.