Steps to reproduce:
1. Open attached project in Unity 2022 LTS
2. Open scene Colliders_MoverInHierarchyComplex.unity
3. Enter playmode and capture CPU performance using profiler
4. Make a copy of the project and open it in Unity 6, then repeat the steps above
5. Compare results
6. Repeat exercise but this time building both versions for a less powerful platform
Although this is a regression on all platforms, the numbers add up very quickly on lower powered device such handheld consoles and low/mid spec mobile devices.
Actual results:
Syncing Physics colliders is about 3-7 times slower in Unity 6 compared to an identical scene in Unity 2022 LTS.
The variance in regression comes from scene configuration and complexity, but certain complex hierarchy configurations that were already a bit slow in 2022 LTS are now significantly slower in Unity 6.
Expected results:
Cost of syncing transforms in Unity 6 is on par with or lower than cost of syncing transforms in Unity 2022 LTS.
Reproducible with versions:
6000.0.26f1
Not reproducible with versions:
2022.3.20f1
Tested on (OS):
Windows
macOS
Android
Notes:
For a point of reference, testing the included repro on a low-powered Android device it spends about 3 ms / frame syncing transforms in Unity 2022 LTS and 15 ms / frame in Unity 6 - so 5x as long in U6.