The XR-55X90K is a 55 inch 4K TV from Sony. It was launched in 2022. It features a True 10-bit VA panel.
It can display a max resolution of 3840 x 2160 with a refresh rate of 120 Hz and pixel density of 80 ppi.
Picture Quality
After screen size and resolution, the next important feature to look for in a display is its Color Reproduction Accuracy (defined by its color gamut specification).
Sony has not provided a color gamut rating for this TV. But don't worry, we have other means to guess that.
Considering the TV features a 55 inch screen, it won't come with a cheap panel, so here we can assume its equivalent sRGB coverage to be 90-100% or above. The color quality on this TV will be Lifelike! Meaning it is capable of producing color accurate images out of the box.
Understanding Color Gamut
Color gamut spec of a TV is a measure of the range of colors that the display can show.
Put Simply, it tells the ability of a TV to produce accurate colors. A display with low gamut coverage will miss out on some colors (such as deep red), the result would be a "washed out" picture quality.
Different manufacturers use different units to define color gamut. Such as — sRGB (most popular), NTSC, DCI P3 Adobe RGB and rec.2020.
But don't worry, below is a chart that you can use to choose a TV with good color accuracy.
Now, after color gamut, the static contrast of a TV also impacts its picture quality.
Why its important?
The static contrast ratio of a TV corresponds to its Black levels. A Display with low static contrast ratio (<1000:1) will not produce deep blacks. Also, such TVs often suffer from backlight bleeds such as below:

Needless to say, this will rob your experience considerably, especially in a dark room.
Think of static contrast as another dimension to details — just like resolution. To put it into perspective, a TV with low contrast ratio will produce less shades of colors, so lesser detail overall.
If given a choice, always prefer a FHD TV with high contrast ratio over a 4K TV with low contrast ratio.
This TV comes with a static contrast ratio of 8000:1., good enough to produce deep blacks and eye-catching visuals. The panel comes with local dimming technology which is a plus.
Dolby Vision, HDR10 and HLG (Hybrid Log Gamma) are also supported on this TV, so that's a plus.
Coming to brightness, the peak luminance the Sony XR-55X90K can produce is 250 nits with the help of Direct LED (Full-Array Local Dimming) backlight.
Gaming Performance
If you are planning to use your TV only for content consumption, you can ignore these specifications. But if you are also going to use the TV for gaming or use it as a PC monitor, make sure to get a TV with the lowest input lag and response time.
Sadly, we cannot find the input lag specification for this unit. Now, since this is not a cheap TV from Sony, input lag on this TV could be 20ms or below.
Understanding Input lag and response time
This lag is the amount of time at which inputs changes the content of your display. For casual Non-FPS games, input lag doesn't matter much.
Although for better experience, look for a TV that has an input lag and response time of < 20ms.
Ergonomics and Dimensions
Coming to ergonomics — VESA mount is supported on this TV with an interface size of 300 x 300 mm. The unit doesn't come with Swivel, Tilt or Pivot support.
The width of this TV is 48.54 inches while its height is 30.83 inches ( adjustable upto 1.57 inches ).
Coming to thickness, it is just 2.83 inches thick. It weighs approximately 17.4 KGs, another 1.1 kgs if you include stand.
Hardware and Audio
The TV comes with a Quad Core CPU. There is no information on the total available RAM on the TV's official specsheet.
For display connectivity, there are four HDMI 2.1 ports and one AV Composite In 3.5 mm jack port on this TV.
For connecting USB devices, it includes two USB ports. Other connectivity ports include — 1x Satellite In (F-type female), 1x Antenna (RF) (female), 1x CI+ 1.4 and 1x Ethernet RJ45.
For connecting to this TV wirelessly, the manufacturer has provided a 5Ghz Wi-Fi, 2.5 Ghz Wi-Fi, Wifi-Direct, Bluetooth and DLNA.
The Audio unit of this TV is powered by 2 x 10W speakers.
As for power usage, on average, it uses around 113.28W. On standby, it takes 0.5 W.
Both 110V and 220V lines are supported on this unit.