UHD KU6400

Released 2016

Samsung's 2016 flat 4K LCD series with Crystal Colour, HDR signal support and Tizen smart TV software, sold in five sizes from 40 to 65 inches.

Sizes: 40–65″
Panel: LED LCD
Refresh: –
HDR: HDR10
HDMI 2.1: 0 of 3
Software: Tizen

What reviewers say

Digital Foundry and Tweakers liked the 40-inch model's low gaming lag, deep blacks and accurate colour, but found HDR presentation limited. Digital Foundry criticised film judder and dark-scene ghosting; Tweakers noted restricted viewing angles and basic build quality. Both saw it as a useful large PC or console display.

From eurogamer.net and tweakers.net

Specifications

Report a wrong or missing spec

Display

Panel: LED LCD
Panel detail: Flat LCD with LED backlight; VA panel on the 40-inch Digital Foundry and Tweakers review units. Panel type is not assigned to the other sizes.
Resolution: 3840 × 2160 (4K)
HDR formats: HDR10
Peak brightness: Digital Foundry measured 400 nits peak brightness on its 40-inch sample; Tweakers measured 380 cd/m² at maximum backlight on its 40-inch sample. These are review measurements, not maker ratings.
Picture processing: Active Crystal Colour, UHD Dimming, Contrast Enhancer and Auto Motion Plus. The maker's PQI 1500 and Motion Rate 100 labels are not native panel refresh rates; native Hz is left unpublished.

Sizes

Sizes: 40, 43, 49, 55, 65″
Largest size: 65″

Gaming

HDMI ports: 3 (0 HDMI 2.1 at 4K 120 Hz+)
Variable refresh rate: None
Auto low latency mode: No
HDMI detail: Three HDMI inputs with ARC and HDMI-CEC. Tweakers confirmed HDMI 2.0 and 4K 60 Hz PC input on its 40-inch European sample; enable HDMI UHD Color for full chroma text reproduction.
Input lag: 21 ms in Game Mode on the 40-inch Tweakers sample. Digital Foundry lists 21 ms in its specifications table but 19 ms in its text; the conflicting figures are not combined.
Game features: Manual Game Mode; no variable refresh or automatic low-latency switching.

Smart TV and sound

Smart TV platform: Tizen
Processor: UHD Up-Scaling picture engine
Speakers: 20 W, 2.0 channels
eARC: No
Wi-Fi: Built-in Wi-Fi
Speaker detail: Two-channel down-firing bass-reflex speakers with 20 W total output.
Audio features: Dolby Digital Plus, DTS, Multiroom Link, TV SoundConnect and Bluetooth headset support.
Software updates: Tizen smart TV platform; original app availability is not guaranteed today.
TV tuners: Samsung's UK API lists DVB-T2 for 40 inches and DVB-T2/C/S2 for the larger sizes. Its regional app and tuner entries differ, so satellite support is not assumed for the 40-inch model.
USB: Two USB ports with media playback, recording and time shift.
Ethernet: Ethernet LAN port.
Optical audio out: Optical digital audio output. Digital Foundry describes a headphone output, while Tweakers reports no 3.5 mm socket; no analogue headphone output is assigned.

Design and power

Size: Width × height × depth without stands, from the UK manual: 40-inch 905.7 × 520.6 × 54.6 mm; 43-inch 968.8 × 565.2 × 55.4 mm; 49-inch 1101.4 × 639.7 × 55.2 mm; 55-inch 1237.2 × 716.1 × 55.2 mm; 65-inch 1458.1 × 841.4 × 54.9 mm. Configuration weights exclude stands.
Stand: Fixed stand with no swivel. The UK manual overrides conflicting online table dimensions for 40 inches and with-stand height/depth for 55 inches. With-stand weights are 11.5, 12.7, 17.1, 19.6 and 26.8 kg respectively.
In the box: Samsung Smart Remote, batteries, power cable, manual and analogue breakout cable; additional remote wording varies by size in the maker tables.

Sizes

Size	Model	Weight without stand
40″	UE40KU6400UXXU	9.2 kg
43″	UE43KU6400UXXU	10.5 kg
49″	UE49KU6400UXXU	14.4 kg
55″	UE55KU6400UXXU	16.9 kg
65″	UE65KU6400UXXU	23.5 kg

Pros and cons

Pros

4K resolution with HDR10 signal support
Three HDMI inputs and two USB ports
Built-in Wi-Fi and Bluetooth headset support

Cons

No HDMI 2.1 or variable refresh support
No Dolby Vision support
Original online apps may no longer be available

Closest rivals

Model	Sizes	Panel	Refresh	HDR	HDMI 2.1	Software	Released
HisenseA7S	43–65″	LED LCD	60 Hz	Dolby Vision, HDR10+	0 of 3	VIDAA	Jan 2026
PanasonicVIERA AX902	55–65″	LED LCD	–	None	0 of 4	my Home Screen	2014
PanasonicVIERA CX802	40–65″	LED LCD	–	HDR10	0 of 3	my Home Screen	2015

Sources

Photo: Maker front view retains the original UHD TV and Ultra HD screen badges; no clean manufacturer render was available from the model support page.

Spot a mistake? Tell us