The uj6540 review has an amazing picture quality thanks to the 4k resolution. The display features active HDR which offers bright and colorful images with astonishing clearness. It also has local dimming which dims the backlight of the screen where the colors are black thus improving the contrast even more. The color accuracy is also pretty good but not as great as on some other LG TVs, especially with the blues and cyans. The gamma curve is not very flat but still close enough to the 2.2 target.
The input lag is quite low which makes it very responsive when used as a PC monitor. The response time is also decent and only leaves a short trail when following fast-moving content.
However, the IPS panel does have some problems with temporary image retention which can cause a static image to remain visible on the screen for a few minutes after the source is removed. This is a common issue with some IPS panels but it isn’t as bad on this model as the uj7700 from last year.
The sound performance is pretty good and the LG’s magic audio tuning feature really helps to improve the clarity of the dialog. The built-in speakers are pretty powerful and can easily fill a small to medium sized room with clear and crisp sounds.