The Sony FWD-65X8600 has a maximum display resolution of 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.
A 4K Ultra HD HD type is in fact the best display resolution amongst all televisions of this age and type.
Amongst similar types of television the worst display resolution is Full HD.
4K Ultra HD TVs have a resolution of 3840 x 2160 pixels.
There are a number of alternative 4K Ultra HD TVs currently available that you might want to look at including because of it's better review score, the LG 55LA970, the Panasonic TX-65AXW804 (£3,499.85), or the Samsung UE55F9000.