Mini-Review: Samsung 40KU6400 as a monitor

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This is just a small mini review of the Samsung UE40KU6400 UHD TV used for PC / Console duty.

It's not going to be a scientific affair, more my setup and impressions using it as a PC monitor and for my Games consoles.

Reason for choosing a 40" UHD TV as a PC Monitor:
I recently purchased a 34" Superwide for work (Dell U3417W), this is a good enough monitor but if buying a monitor myself, I felt I'd like a bit more screen real estate.
Initially I looked at the LG 38" 21:9 monitor, but at £1K it seems poor VFM at the moment. Doing some quick man maths, I quickly worked out that a 38" superwide is pretty much the same width as a 40" display, so naturally I started considering 40" 4K Offerings which would be the same horizontal dimensions but add more height/pixels/real-estate.

After searching for a couple of hours, I accidentally stumbled across the Digital Foundry review of the Samsung 40" TV which concludes:
While you don't get all the full bells and whistles of a higher end 4K set - HDR performance is limited here - the extra pixel density, high contrast ratio and low input lag allow for a superb gaming experience in standard dynamic range. Combined with Smart TV functionality and very good performance in most areas, the KU6400 easily outclasses high-end 1440p and 4K PC monitors costing considerable more, and works well as an affordable HDTV for UHD gaming.
and at £480 with a5 year warranty, it seemed something worth trying, especially after seeing other feedback about the KU6400 (KU7000 in the US) around the web.


Initial Impressions
kWssHcD.jpg

The monitor looks great on the desk, the stand has a brushed metal finish that matches the thin brushed lower bezel, and is just about the perfect height since the screen is quite tall it gives as comfortable a view as you can expect sat so close to a large display. I've tried raising it up but found it uncomfortable panning your head around the screen.

Just plugging in the PC immediately was impressive, the detail and clarity of the desktop was sublime with almost too much contrast with the out the box settings.

Setup and IQ Tweaking
For PC use, I am feeding it from an ASUS Strix GTX970 via a HDMI 2.0 cable.
The input has been set to 'PC' which automatically defeats just about all processing options, and then the HDMI colour space expanded to UHD Color (4:4:4).The Nvidia control panel was then used to set 8 bit colour and 4:4:4 colour encoding.
I confirmed all this using this simple test on a webpage ((4:4:4 Check).

The next step is due to my photography hobby I calibrate all my displays, in this case using an i1 Display Pro. As per the DF Review, you do indeed need to set the white balance to WARM 2 and from there it's just a small tweak of the RGB channels. The out the box calibration isn't too bad at all, if I switch between a default colour profile and my calibrated profile, the differences are only marginal.
I confirmed using imaging resources simple calibration test ((here) that I can just differentiate RGB values of 5 and 254, thus ensuring I can fully see all highlight detail and black level detail.

IQ Notes (PC Use)
Being a VA Panel, the black levels are excellent, although in PC Mode calibrated, all processing options that might minimise black levels on dark screens are defeated, so you do get a slightly elevated black level that is possible, but it's still very good indeed.

Viewing angles are much better than expected, my previous 28" TN panel had low but noticeable levels of clouding and loss of contrast in the corners due to the viewing angles, but this larger 40" manages to better that by a degree, and it is only the bottom corners that show signs of viewing angle colour/contrast drop off which is minor.
The only other viewing angle related issue (an artefact of sitting so close) is that backlight bleed is ever so slightly visible in the lower corners. If you move your head around this diminish to almost nothing, so viewing distance/angle can minimise those, however on the supplied stand that is the only observation and does not bother me at all.

Colour uniformity is largely superb, editing photo's is a joy, being able to have side by side comparisons and still see the entire image in enough detail has sped up my workflow no end.

Interestingly I have found input lag to be low even with 4:4:4 colour enabled @ 4K, I think when you configure the input as 'PC' it turns off all processing and you don't get any options such as gaming mode, I think it immediately goes for the lowest level of input lag (assumed 20ms).

Console Usage Notes
The other source I'm using at the moment is an Xbox One S. In this mode, it's using 4K @ 60hz in gaming mode, this drops the colour space ever so slightly so you aren't getting the full 4:4:4 colour, but as yet I have only been blown away by the colour and detail the monitor seems to pull out the image, and playing Gears of War 4 or Destiny has really been an improved experience.
Input lag is good (20ms apparantly) and most certainly in gaming mode has performed identically to both my monitors I normally use.

HDR and why it's not that amazing
Well, as per the DF review, this set although labelled as HDR is not a HDR capable TV in that it can't render HDR10 or Dolby Vision, so whilst it can accept a HDR signal, it won't technically get the most out of it.
However this leads me onto the whole subject of HDR which I feel to some degree is the emporers new clothes.

Having used a Samsung KS9000 for a truer HDR experience, I found that it's the ridiculous light levels (1000nits!) that really makes it too contrasty and actually hurts my eyes if gaming up close or using it as a PC monitor for any period of time. I do welcome the wider gamut, but would still reduce the white level down to the 200-250 nits level to be comfortable.

In that regard, the KU6400 is adequate, it's has a wider than normal colour gamut, which elevates it above most dedicated monitors immediately, and it's native contrast is very good (I think it measure somewhere between 3000-4000:1) and it's maximum output of around 400 nits is actually too much for me, I end up turning this down to be comfortable.

Other Features
And this is where the TV shines, it has a great set of apps built in, the Amazon prime video app allows Ultra HD streams to be played, and so far everything I've used seems to work well enough, it's not too slow and seems to find every media source on my network automatically:
RTFQKMT.jpg
And this is backed by a good enough inbuilt speaker setup, they are in a down firing configuration, with good volume, decent enough bass for general youtube/console use. I do however use a proper HiFi setup for PC music/gaming and 5.1 headphones for console use.


Conclusion
Technically this TV lacks many motion processing modes that do tend to get noted in reviews when using this as a TV, however, used in Gaming mode for consoles and setup for PC use as a monitor, this TV/Monitor seems to excel, pretty much as Digital Foundry say, the wider colour gamut, the black levels, and the general performance of this 4K monitor make it excellent value for money.

The fact it can make some use of a HDR signal is a bonus, and if you are someone that wants more real-estate and doesn't mind sitting close to a display, this is certainly very good VFM.

People who want 144hz PC gaming nirvana need look away, those monitors should 4K monitors should appear next year, but I suspect in a different league of pricing as well.

Overall, I'd give it 8/10 and couldn't be happier.

When 40" curved 144Hz HDR G-Sync monitors come out under £700 I will upgrade, but I sense that'll be a couple of years yet..
 
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@Demon
thanks mate. Also have you tried gaming with the PC? I know the 970 will run out of steam, however how was input lag, image quality while gaming, ghosting etc?

Input lag is difficult to judge, however, I have compared modes/inputs using the reaction time test (average of 5 goes, link)
Input Set to PC, 4:4:4 colour, 4K 60Hz gives me 273ms
Input Set to Console, Gaming mode on (4:2:2) 4K 60hz gives me 277ms

So I'd say that since I know Gaming mode with 4:2:2 colour is 20ms input lag, and considering my reaction time is pretty much bang on average, that alone seems good enough to me to suggest PC mode is 20ms or there abouts.. I notice no discernible lag at all.

Ghosting, I've tried a few things, e.g. http://www.testufo.com/#test=ghosting and to be honest it's very minimal, almost no streaking at all, easily better than my previous TN monitor.

Thanks op for this, I'm in the market for a bigger screen and generally need it for standard desktop work and photo editing, I may also use it for a little gaming but likely from my xbox.

I'm just scouring the internet for similar threads to see what sets are out there, have you seen any others crop up, I'm assuming this would have no built in modes for split screen etc, which I quite like the idea of on something like the x34 displays. I guess standard windows fixing would still work really well though
The best review is the Digital Foundry review (http://www.eurogamer.net/articles/digitalfoundry-2016-samsung-ku6400-4k-tv-review).

I did look at a few alternate TVs and was tempted by the HiSense 40M3300 since it's cheap but I couldn't find any concrete reviews on it, so in the end went for the Samsung purely on DF's (http://www.eurogamer.net/articles/digitalfoundry-2016-samsung-ku6400-4k-tv-review) and RTings (http://uk.rtings.com/tv/reviews/samsung/ku7000) reviews.
 
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Nice review i wonder what power usage (watts) is like between using a tv as a monitor and using a proper pc monitor anyone know


Absolutely no different IMO, I've just measured mine to confirm and compared to the Philips BDM4065 UC as measured by TFT central: http://www.tftcentral.co.uk/reviews/philips_bdm4065uc.htm)

Philips BDM4065UC:
Manufacturers Quoted Consumption = 77.6W
Measured at manufacturers settings = 81W
Measured at Calibrated Brightness (120 Lumens) = 45W

My figures:
Samsung 40KU6400 Quoted = 62W
Measured at manufacturers settings = 66.5W
Measured at Calibrated Brightness (120 Lumens) = 47.1W

:)

Had mine delivered today but can't have a play until I've finished work at 8.

Demon. Any chance you would be willing to post up a brief overview of your settings, please? It'd be cool to use them as a place to start and then tweak to taste from there.
No probs:

PC Setup
Input set to 'PC' (Highlight the HDMI 'source' icon and press up, then edit, then select PC)
Picture Mode - Standard
Special Picture Mode - This says 'SPORTS' but is actually turned off when you drill down in that menu.

Expert Picture Settings:
Backlight - 8
Brightness - 49
Contrast - 99
Sharpness - 50
(Everything is now greyed out between this and the next option)
HDMI UHD Colour -> HDMI the PC is connected to is 'ON'
(more greyed out stuff)
Colour Tone - Warm 2
White Balance -> 2 Point ->Red Gain 14 / G Gain -3 (all others 0)
Gamma - 0

When you select 'PC' as the input type a lot of stuff is greyed out so there isn't any other adjustments to make.

This is for 2.2 Gamma, 120 Lumens, D65 white point which is the normal monitor calibration target as per TFT Central etc.
 
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Hi all,
Really interested in this monitor but some reviews say that motion can get blurry and jutter during movies, does this have any impact when using it as a monitor for gaming.

Two things on this subject
1. PC Monitors offer no video processing of note, and when set in PC mode on the Samsung it acts as 'dumb' as a PC Monitor in that regard, i.e. as with a PC Monitor, supply it 60fps and it's 'smooth', supply it 25hz and it'll look like a PC monitor would, jerky..

2. It actually has quite good motion smoothing processing options if you set it up as a TV and play things like Amazon prime through it. I think the comments in reviews are really comparing it to TVs costing 2-3 times as much which handle a wider range of odd ball cases, like 24Hz where motion handling needs extensive processing.

I've actually been impressed with it's motion handling in video, and I've even turned it on when playing 30fps games on the Xbox for a much smoother rendition, although I find the input lag intrusive so switched the motion processing back off for that.
 
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I thought I'd try Gears of War 4 on PC to see what my GTX970 could do, and I was not surprised that 4k requires lowish settings which make the game look terrible, so I messed with the settings and for a rock solid 60fps, it will handle 2160 x 1440 on Ultra with the dynamic resolution set to 50%.

Absolutely so much more playable than the consoles 30fps, and slightly improved IQ throughout even at double the framerate.
 
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Scrap that, looks much better now I've re-calibrated. Loving it so far, however it's taking a little adjusting to over my 27" 1440p monitor, however photo editing is an absolute joy now with such a large amount of real estate.

I get almost no black crush even uncalibrated it might be worth checking your settings:

On the PC, Nvidia Control Panel I have
Desktop Colour Depth: 32 Bit
Output Colour Format: RGB
Output Colour Depth: 8 bit
Output Dynamic Range: Full (This is important)

And on the TV, ensure "HDMI Black Level" is normal and you have set HDMI 1 to UHD Colour 'On'..

I found the HDMI Black Level set to auto is actually defaulting to 'low' which is limited 16-235, so this needs to be 'normal' to match the full dynamic range setting in the Nvidia control panel.#

You should be able to get very close to seeing all black/white blocks even without calibration on http://www.imaging-resource.com/ARTS/MONCAL/CALIBRATE.HTM

But calibrated, it's great, I can see all black/white levels
 
There is a great deal of similarity in terms of features.

The main difference is in the Crystal Colour (I think this is part processing, part pixel drive circuitry), this gives it a slightly wider colour gamut (86% vs 83% DCI-P3) and as stated above, slightly increase PQI (1500 vs 1300)..

It also has slimmer bezels if that counts for anything.
 
What they like or any other TV on the eyes when used for long periods of 8 hours or more of productivity and not gaming.

Exactly the same as any other monitor really, I have zero issues using a Dell 3417W at work, to this at home for 4-6 hours at at time, it just feels like a large monitor because I guess it is!

Just received this monitor as decided to go with a TV rather than IPS ultrawide (and save myself a fortune in the process). Overall i'm pleased with the image quality but there is some black "smudging" along the bottom of the panel which is noticeable on lighter backgrounds.
Is this normal for a VA panel? Whilst noticeable it doesn't bother me that much to warrant a return unless anyone thinks it's unusual?
https://www.dropbox.com/s/iu84cmixyq209j1/IMG_20170221_103720.jpg?dl=0
Thanks
Yeah, right at the very bottom mine is a bit like that.. and so is my Dell 3417W in work, I think it's where the panels are clamped at the edges you can get this kind of pressure marking.. but on mine it's hidden by the Windows Taskbar the majority of the time so ignore it.
 
Thanks, I will give this a go. But I think the real problem is that I cannot get the chroma4:4:4 mode to work correctly above 30Hz and it is driving me mad.:mad::mad::mad::mad::mad:

The issue is the Sammy MU6400 fails the chroma sub sampling test spectacularly at 60Hz - it’s almost unsalable as I get a headache after an hour or so.

I have a GTX 1080Ti so I have been trying to set the Output colour format in the Nvidia control panel to chroma YCbCR444 @ 60Hz without success

I have tried (all connected to HDMI port 1 on the TV):

  • 2 different “high speed” HDMI cables where the best stable output format YCBCr420 @ 60Hz
  • Same HDMI cables and active display port adapter which will give the option to select YCbCR444 but only at 30Hz
  • Display port cable again only allows YCBCr420 @ 60Hz

For the Sammy MU6400 to be usable the I need YCbCR444. I assume there is something wrong with my cables.

So my question how do people get the Sammy to pass the chroma sub sampling test at 60Hz? What settings do you have and which connectors are you using?

These where my settings:


PC Setup
Input set to 'PC' (Highlight the HDMI 'source' icon and press up, then edit, then select PC)
Picture Mode - Standard
Special Picture Mode - This says 'SPORTS' but is actually turned off when you drill down in that menu.

Expert Picture Settings:
Backlight - 8
Brightness - 49
Contrast - 99
Sharpness - 50
(Everything is now greyed out between this and the next option)
HDMI UHD Colour -> HDMI the PC is connected to is 'ON'
(more greyed out stuff)
Colour Tone - Warm 2
White Balance -> 2 Point ->Red Gain 14 / G Gain -3 (all others 0)
Gamma - 0

When you select 'PC' as the input type a lot of stuff is greyed out so there isn't any other adjustments to make.

This is for 2.2 Gamma, 120 Lumens, D65 white point which is the normal monitor calibration target as per TFT Central etc.


On the PC I found the Windows 10 CC update screwed things up and the TV was going in to HDR mode and the PC defaulting to 10 bit at some weird colour encoding. To stop that happening, I set the Nvidia output to 8 bit colour, full rgb rather than 4:4:4
I used this link to check for correct 4:4:4 handling http://www.geeks3d.com/20141203/how...-chroma-subsampling-used-with-your-4k-uhd-tv/

All back to normal and working again
 
Nice to see the thread still going!

I might replace my Dell Ultrawide 34" in work with another 40" HDTV, I just love the real-estate it gives at home. As soon as I show people it in my study and tell them the price, they can't believe it! I've been doing more 60hz gaming on it recently and still really love it as an all-rounder. The only improvement I'd like is more HDMI 2.0 inputs, so just reading up now on the other TV's you've all been getting!

Interesting thread! I've been looking at 27" 2k/4k monitors and more recently, 34" ultrawide. Then I saw this thread and it's got me thinking about 40/43". I'll have a proper read over the weekend but maybe someone who owns a Samsung MU6400 could give me their opinion (or similar model like the Sony KD43XE8396.

I'm no pro but I want something that will give me fairly accurate colours for editing pictures. Do these 4k TV's cut it or should I really stick to ips monitors?

If you are serious about photo-editing and want accurate colours, you pretty much want to buy yourself a colorimeter, I use the i1 Display Pro, but a colormunki or spyder would be good start, it's the one way to guarantee accuracy on all your PC monitors. I did the KU6400 and that is absolutely bang on for SRGB photo editing.
 
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