HDRP Performance Regression After Upgrading from Unity 6.2 to 6.3

[Qleenie]

We saw similar performance regression going from 6000.0.63f1 to 6000.0.71f1… We are using DX11. Also after updating, shader compile errors starting to appear related to UnityTexture3D, so there was definitely a deeper change somewhere. BTW error happens on a Unity owned package (hair package). This is not good to have this deep of changes on minor LTS versions without any warning (at least i did not find any, going carefully through all release notes of 6000.0.64 to 6000.0.71).

Performance regressions we see are all GPU related. The regression on Unity 6 LTS line only affects the hair package, but updating to 6.3 affects most of our compute shader (not render graph, though).

Edit: Made a separate thread for the Unity 6 LTS related issue:

Updating from 6000.0.63f1 to 6000.0.71f1: Big performance regressions and shader error related to UnityTexture3D

As the title says, we observed two things after updating Unity from 6000.0.63f1 to 6000.0.71f1 in our production project (DX11 / URP): shader code using UnityTexture3D did not compile anymore (in this case from Unity’s hair package) we observed a big performance hit (GPU time) on same package after fixing the compile issue (by initializing “hdrDecode” zero values). Whatever has been fixed in one of the updates between 6000.0.64 and 6000.0.71 completely destroyed GPU performance in our projec…