no tiles while rendering, picure builds from bottom since i edited file on an old laptop for once I have used an old laptop to edit a blender project and now when I hit render on my regular machine I do not see the familiar tiles.
the picture is build up from the bottom and is then sharpened with each sample run. 
Tiles are set to Hilbert Spiral, but other choices do not change how it renders
The original unedited file still renders in tiles.

I have no idea if this has any consequence as to image quality or render time.
But if so, how do I change back to rendering in tiles.
Or do I have to redo the original file on my regular machine to fix this?
It sounds like the "progressive refine" option is checked.



Progressive refine will render the entire image one sample at a time similar to how the viewport does it. This does not affect the quality of the output, but it does affect the speed as progressive refine is slower than rendering all samples per tile.