if rendersize is bigger than 4000 pixel, the picture is rendered in two tiles.
Sample rendering: e.g. 100 samples - 100 samples first tile and again 100 samples second tile
Time rendering: e.g. 5min, 2,5min first tile, 2,5min second tile
Yes, true That's because it's exceeds your computing displayed size of your graphics card. So the rendering is just cut in two parts. In bigger sizes, it cut the rendering in 4 if I remember.
But in any case don't be affraid, it's only during the computing/rendering time, at the end you have a full size image!
Thanks for the info Nicolas.Never noticed this before.
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