Shader stutter on new games running on Unreal Engine 4 is a stain on modern PC gaming and developers need to address it sooner rather than later.
If you’ve got a gaming PC and have booted up a game recently, whether that be Jedi: Fallen Order, Final Fantasy 7: Remake, or, as I experienced, Like a Dragon: Ishin, you might encounter something named shader stutter. The effect this has on games stems back for years, and only a select few games have managed to optimize themselves well enough to avoid the issue entirely.
The toxic combination of factors appears to stem from multiple things. Firstly, many of the games with stuttering issues appear to run on the same core engine, Unreal Engine 4. Secondly, shader stutter can also be caused by DirectX12, and more specifically, the Vulkan API.
You might expect some hitches here and there with a lower-end gaming system. For titles that run on older-generation consoles, you would think that our usual gaming PC would be up to the task. It is equipped Ryzen 5 3600 paired with an RTX 3080 and a speedy SSD. So, should be enough to handle just about anything.
Sadly, this appears to not be the case in Like a Dragon: Ishin, which is severely impacted by shader stutter, impacting some of the game’s most crucial moments.
Some developers manage to avoid this entirely
Some games, like Hogwarts Legacy, manage to sidestep the shader stutter issue by caching them upon boot. Others in the seemingly afflicted Unreal Engine 4 manage to sidestep this entirely, as an article with Tango Gameworks developers from PC Gamer explains.
“When a game loads a shader for the first time, GPU drivers begin compilation causing hitches. Devs spend a lot of time replaying the same scene, so tend to miss PSO [Pipeline State Object] compile-related hitching.”
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Basically, when you replay the same section with the shaders loaded onto your GPU, you’ll not have any stuttering issues, so when developers test the title, this element can often be overlooked. When combining more than one shader for a flashy effect, the issue can also be exacerbated, as the interview tells us.
If a game does not perform any precompilation through the use of loading screens, in the background, it’ll load in on the first use, which is the source of the issue.
Developers need to do better
Why is this happening in 2023? The issue appears to stem all the way back to how the Unreal Engine interfaces with the Vulkan API, with little hope in sight for developers to actually address the issues beneath them. Unreal Engine 5 seems to solve some of these issues, with Epic putting in extra effort to ensure that these compilation issues do not happen. But, what about all of the games running on Unreal Engine 4?
Unless developers pay special attention to shader loading issues during development, it’s possible that some of these games will simply be left to rot with a sub-par port that runs perfectly well on hardware that is inferior to most gaming PCs.