Running some quick tests on Windows and Linux, these were my observations:
Blender 4.0 is generally slower than older versions of Blender. As is expected based on testing done for other things. And on Linux with Intel Arc, the performance drop is worse than Windows.
However, with Blender 4.1 and 4.2, Linux performance appears to be back to normal. To my knowledge, Blender 4.0 is no longer seeing corrective releases, so this just seems to be a issue people need to deal with until 4.1 officially releases.
For reference, here are the performance numbers for Linux (Measured in time per sample, lower is better):
Note: This graph was automatically generated by the Blender performance benchmarking script. Some of the scenes don’t have labels. The scenes are Barbershop, Fishy Cat and WDAS Cloud.
Some of the normal benchmark scenes are missing (Spring and Victor). Victor is missing due to VRAM limitations. Spring was removed due to a bug.
Note 2: These are just quick tests. Some of the performance numbers (E.G. 3.6.0 vs 3.6.9) may need investigation, or it could just be testing noise. If they are just testing noise, then it invalidates all the observations mentioned above.
Edit for note 2 above: A 9% performance regression in 3.6.9 is apparently “expected”, but Intel is looking into it.