Corona light sample problem

[ileste]

I want to make brush metal I put normal map on the bump slot with very fine thin lines.
When I render with lighting form HDR everything OK, but when I render with corona light sphere the lines of the grooves are pixelate and there is noise.
I tried to blur the normal map, increase corona light, increase light samples, increase GI vs AA no success.
Or there is also noise when I render with HDR but I don't see clearly because it is masked with the other parts that reflect the HDR.
I attach the normal if there is something wrong with it.

[maru]

I would say that both results are fine, but the hdri light is more uniform, so it is harder to see any imperfections.
You can also try swapping red/gree/blue channels of the normal map to make sure it is loaded correctly.