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Epic Games adds new PSO precaching mechanism to Unreal Engine 5.1 to reduce shader compilation stutters

Epic Games has added a new PSO precaching mechanism to Unreal Engine 5.1 to improve PSO hitching in DX12 titles. This new mechanism will attempt to reduce the shader compilation stutters in future DX12 games (provided these games support this new mechanism).

Going into more details, the new PSO precaching mechanism now skips drawing objects if their PSOs aren’t ready yet. The system aims to have the PSO ready in time for drawing, but it will never be able to guarantee this. When it’s late, it is now possible to skip drawing the object instead of waiting for the compilation to finish. This will ultimately reduce shader compilation stutters.

Furthermore, Epic has reduced the number of PSOs to precache. Not only that, but the team has improved the old (manual) PSO cache system. As such, developers can use it alongside the new precaching mechanism.

You can find more details about the new PSO precaching mechanism here. Also note that these improvements are exclusive to Unreal Engine 5.1 and up. In other words, older games will not benefit from it.

Anyway, this is great news so let’s hope that developers will take advantage of it in their upcoming games!

Unreal Engine 5.1 | What's new for Film, Broadcast, Animation, and Live Events