The 40UF671 has a maximum display resolution of 4K Ultra HD. That's over four times the display resolution of the most frequently found HD type of Full HD. 4K Ultra HD TVs have a resolution of 3840 x 2160 pixels.
This television's display resolution (4K Ultra HD) is actually the best display resolution amongst all similar spec TVs that were launched around the same time as the 40UF671.
An HD Ready HD type is the worst display resolution across similar types of television.
4K Ultra HD TVs have a resolution of 3840 x 2160 pixels.
It may also be worth also looking at one of the other 4K Ultra HD TVs currently available including because of it's better review score, the LOEWE Connect 40.