The highest resolution of the 27UD68-W is 3840 x 2160. That's over four times the resolution of a 1920 x 1080 (HD 1080) PC display, which is the most frequently found resolution. 1920 x 1080 (HD 1080) is also found on this flatpanel monitor.
This PC screen's resolution (3840 x 2160) is in fact the best resolution amongst all recently released medium monitors.
The worst resolution amongst similar types of PC screen is 640 x 350.