The highest display resolution of the 40PUS6809 is 4K Ultra HD. That's over four times the display resolution of the most common HD type of Full HD. 4K Ultra HD TVs have a resolution of 3840 x 2160 pixels.
This TV's display resolution (4K Ultra HD) is actually the best display resolution amongst all televisions of this age and type.
Amongst similar types of TV the worst display resolution is Not supported.
4K Ultra HD TVs have a resolution of 3840 x 2160 pixels.
It may also be worth considering one of the other 4K Ultra HD TVs currently available including because of it's better review score, the LG 42UB820 (£399.00), or the Samsung UE40HU6900 (£617.99).