Does Diablo 3 patch 2.4 impact console performance?
Digital Foundry follows up on community reports of unstable performance from the latest update.
Blizzard's latest Diablo 3 console patch 2.4 is understood to cause frame-rate issues not seen in the previous version. The update adds a range of compelling extras, like a new Greyhollow Island area, expanded zones, and a catalogue of tweaks per class and weapon. But reports on the game's official forums suggest performance has taken a serious a hit in the meantime, and controls are now laggier as a consequence - while menus suffer input delays. Also worrying are reports of more frequent in-game crashing.
With thanks to Eurogamer's Oli Welsh and his up-to-speed PS4 save, we've managed to isolate some of the challenges players are experiencing in the video below. In particular, the issue manifests as a stutter when travelling the game world, even while uncontested by enemies. And surprisingly, these frustrating hitches remain even when the game is installed to a nippy SSD, strongly suggesting it has little to do with data streaming from a PS4's stock HDD.
Though most interior areas run at a clean 60fps as expected, larger outdoor spots like Southern Highlands, or Dreadjudge Approach show frames dropping in clusters without any real provocation. Simply moving quickly - whether that's via a Barbarian's leap move, or being knocked back by an enemy - is one of the easier ways to see the stutter in action. Even simply walking across a bridge, without an enemy in sight, produces the issue, as demonstrated in our video below.
These one-off hitches are a distraction, but pale in comparison to some of the choppier playback we see in actual combat. Even playing entirely solo (in this case as a level 70 Barbarian in Dreadjudge), Diablo 3's current patch shows drastic frame-time spikes when engaging with a screen filled with enemies. The target for a 60fps title is a consistent 16.7ms render time per frame. But out of the blue this can chop down to around 200ms - a fifth of a second - as our lowest recorded figure. This means drops down to 40fps - and an immediate return back - are something to watch out for.
It's hard to overlook during hectic rift challenges, as geared towards the more savvy Diablo 3 player. At its worst, this variable refresh creates a de-sync between character movement and the controller input. Simply put, frame-rate drops aren't the problem alone - but rather, the more jarring aspect is the wildly uneven rate at which frames are arriving to the screen in these big battles. It's this aspect that begins to hamper the reliability of each button press, and knowing when to expect a response on-screen.
The cause of Diablo 3's erratic performance on 2.4 is curious. While we have no data point for patch 2.3 by comparison, current analysis indicates Blizzard's engine is capably handling GPU-intensive transparency effects that crop up during hectic combat. To its credit, we see Diablo 3 clocking a smooth 60fps on PS4, even at times where the screen is swamped with enemies and effects. And yet, without warning, the reading will suddenly tank in the middle.
The results can be rough, especially when considering our test is based purely on solo play - and theoretically, demands should increase for four-player co-op. The sharp, disjointed pattern to the graph reading, in this case, is perhaps a sign of a CPU-side bottleneck given the nature and unusual timing of the drops. Whether that's AI, physics, or other calculations running behind the scenes, it's currently unclear what background logic is causing Diablo 3's frame-rate to unravel so noticeably on patch 2.4, where there were few complaints before.
Also tallying with the reports of patch 2.4's stability, we experienced a soft lock - something we hadn't seen prior to this update. With a brand new character set up, Diablo 3 crashed within five minutes on just leaving the New Tristram gates, causing the visuals to hang and music to cycle to a one second loop.
All of which is a concern, given how polished Blizzard's work is in the main. Diablo 3 is something of a rare venture for the studio in recent years, being one of few projects to leave the PC mother nest for a full console release - targeting 60fps, with revamped controls, and four player couch co-op. It remains a committed, full-bodied effort on PS4 and Xbox One - one that's evolved for the better since its 2012 PC release, partly as a result of Blizzard's rapport with its fans. We hope the dialogue continues for this issue as well, and that a console fix arrives sooner rather than later.