Galaxy S8 and S8+ come with 1080p resolution as default, screen goes up to WQHD+
As you can see in this official image from Samsung, it will be doing the same with the Galaxy S8, but the more interesting thing are the exact pixel counts. The screen's actual resolution is now called WQHD+, or the unorthodox 2960 x 1440 pixels, indicating that the rumors about an 18.5:9 screen aspect ratio held water. This new ratio, called Univisium, is similar to what LG did with the G6, and allows for taller, narrower devices.
The default FHD+ screen setting is actually 2220 x 1080, while the new HD+ is 1480 x 720 pixels. Sign of the times, but it remains to be seen if those official battery life numbers Samsung is listing, have been measured with the default FHD+ resolution, or at the full WQHD+ setting. Needless to say, you can always jack up the resolution in the display settings, or lower it down to HD+, if you wish.