Is this normal map ok?

tomii

The normal map has some banding along the edges after baking in Substance Painter. But should not this be a smooth gradient?

Fabi_G

Hi! Looks as intended to me. The values of the border pixel where the UVs end get repeated outwards (edge padding) to reduce visible seams when the texture is displayed at a lower resolution (mip map). I suppose by banding you mean the stepping in the padded pixels? That's probably due to the UV borders not being aligned with the pixel raster, hard to avoid with some elements (e.g. rounded caps).

Does the rendered result look good? 

tomii

I found a section with higher contrast, hope you can see it better here. Can you see the streaks in the dark blue area?

Noren

Like Fabi_G already explained, that seems to be padding (beyond the edge of your UV island) and what matters is what the lowpoly with the normal map applied looks like. Some tools offer other padding techniques than simple pixel repetition, but practically, it shouldn't make much of a difference.