How does tile size affect Cycles render performances in Blender 3D?

While working on my pseudo-minion WIP model, about one month ago, I decided to test how tile size settings affect Cycles render performances in Blender 3D.

I launched five render tests using square tiles of 16, 32, 64, 128 and 256 pixel. The results are summarized in this table.

Tile Size	Render Time
16 px	00:10.59
32 px	00:10.37
64 px	00:10.52
128 px	00:10.68
256 px	00:11.74