OldUnreal (Engine)

I was looking for newer render and installed 227i on my retro machine. I'm playing on a laptop with win xp, ati x1900 and videodriver is dated with 2008 year.

I see seam in skybox and some gap in polygons under certain angle. Maybe there is smth more but that's what i found so far. I'm sadly surprised, but maybe i'm doing smth wrong? I'm using directx9 but same happens in opengl. No such issue in dx8 or glide (via nglide)

The line in the sky is the actual box shape of the sky box. Lines should not be visible but in my experience they are from time to time.
You may want to try different renderers and graphics drivers to see which one works best for you.

Also, Unreal patch 227j should be released in a few days to a few weeks. It also contains fixes to the renderers so that may be worth a try if it is out.

Could be a setting to fix it, like NoAATiles, though I think that only works for 2d?

NoAATiles doesn't seem to help with this issue, but without AA such lines become invisible (on D3D9, OpenGL) or much less visible (XOpenGL). This issue can be seen not only in skyboxes, sometimes such things occur in front of the player right in the map: