4K sounds fun

Story: Better Than a Quad-Head Display: My Adventures with "4K" 2160p and LinuxTotal Replies: 24
Author Content

Mar 31, 2014
1:54 PM EDT
Interesting story. I have 3200x1800 in a 13" laptop and I don't think I can go back to typical resolutions anymore. I've had it for about 6 months.

Mar 31, 2014
2:48 PM EDT
I make carrot juice regularly, but I don't think my Lenovo Y510P laptop with GT750M SLI GPUs is going to handle games under that resolution. I'm not even sure the video cards support that resolution, but atleast nVidia driver is working great on linux, even supporting SLI.

I was going to buy the Oppo Find 7 which is a 1440p phone, but it was the size of a Note 3, so I skipped.

I refuse to call displays base on Ks, I will continue to categorize them base on horizontal lines and progressive or interlaced scans.

Mar 31, 2014
4:21 PM EDT
> I refuse to call displays base on Ks,

You have a problem with color temperature? :)

Apr 01, 2014
8:17 PM EDT
tmx, I agree with you on the terminology point, I'd much prefer a simple statement of horizontal and vertical resolution. This 4K term reminds me of all the terms we went through over the years with computer monitors and notebook displays. VGA, XVGA, WUXGA, WHUXGA, ... the list goes on and on to such a length that it becomes impractical to have all the terms memorized. It's so much easier simply to state the two resolution numbers and be done with it.

I have to say, now that I've used this 3840x2160 monitor for a few days, that I just can't see myself going back to "low-res" ever again. I'm even feeling claustrophobic now while using my 1920x1080 notebook.

Apr 03, 2014
10:47 AM EDT
Dude this is awesome! I want one of these monitors on my desk.

Does anyone know if this will work with a less expensive video card?

Apr 03, 2014
12:56 PM EDT
> Does anyone know if this will work with a less expensive video card?

The specs on your card should list it's maximum resolution.

Apr 03, 2014
1:14 PM EDT
Looks like I'll have to spring for a new video card. Oh well, I can afford $98.

Apr 03, 2014
3:39 PM EDT
I did some Steam (Portal 2) gaming with this Haswell laptop with Intel 4400 integrated graphics card. It worked great at 1600x900 which is exactly 1/4 the native pixels but looks fine. I don't care about super high-res for games as it is limited by the textures anyway. But I do so appreciate it for the text.

Apr 04, 2014
9:54 AM EDT
Reading about this and seeing the photos was irresistible to me and I placed an order for the same monitor and card. I'm looking forward to seeing how this goes!

Apr 05, 2014
2:01 PM EDT
Hey penguinist. Now that you've been running on a 3840x2160 monitor for a week, are you still cool with it?

Any quirks we should know about?

I'm really ready to spring for this, it's just too boss.

Apr 06, 2014
9:03 AM EDT
Quoting:Now that you've been running on a 3840x2160 monitor for a week, are you still cool with it?

Well, after working on a 3840x2160 monitor for a while, I now can add a few things to my report.

1. I will NEVER go back to my old dual low-res monitor setup. This large seamless work surface is definitely a major improvement.

2. I found and fixed an issue with tearing. When playing videos, some minor tearing was noticeable during motion sequences. It turns out that the AMD driver has a setting that fixes this. Setting "Enable Tear Free Desktop" in the driver forces the driver to always wait until the vertical refresh time before painting a new frame. This requires more resources in the graphics adapter to implement, but the R7-240 has 4GB of memory, and that card handles the extra workload with ease. After making this change, I do now have a tear-free desktop.

3. I have been annoyed by the monitor's habit of doing an automatic power-down even though I've set its sleep timer to "Off". I've filed a ticket with Seiki on this point asking for a workaround or a feature addition in the next firmware update. I'll drop their response into this thread when I get it.

4. The last thing I will note is not technical, but is psychological. After getting used to this large display surface, I found myself settling into a screen organization that was working well for me with two pdf viewers looking at documentation, an ide, about ten open xterms, and two firefox windows. Then I wanted to open yet another document and found to my amazement that I had no screen space left without having to minimize something I already had up. Then I realized that it is human nature to let your work expand to fill the space you have available. There is never enough space. For a moment I fantasized about a triple 3840x2160 setup arranged in a U configuration along with a custom-built desk with me positioned at the center, but then quickly settled down to the tried and proven working techniques of minimizing, overlaying, and using multiple Linux workspaces.

In the end, I'm still giving the large surface 3840x2160 monitor a huge thumbs up.

Apr 08, 2014
2:54 PM EDT
Hello. Can one of you run the command:

xdpyinfo and tell me what it says for dimension and resolution? xdpyinfo | grep dimension xdpyinfo | grep resolution

I want to verify how it will behave for LibreOffice. I've been working on making it look good (http://keithcu.com/wordpress/?p=3444), but it needs to detect the DPI correctly and there are a couple of ways to do that on Linux ;-)

Apr 08, 2014
3:50 PM EDT
$ xdpyinfo | grep dimension 
  dimensions:    3840x2160 pixels (1015x571 millimeters)

$ xdpyinfo | grep resolution resolution: 96x96 dots per inch

Apr 08, 2014
5:00 PM EDT
I must finally take keyboard in hand and thank you, penguinist, for this waaay cool article. I may not have the funds (yet!) to try this excellent monster monitor solution, but you can sure bet it's high up on my wish list. Thank you for all your legwork and wonderfully detailed write-up. I bookmarked all of it and have sent the links to a couple graphic artists who I know do have both the jingles and the interest. ;)

Apr 09, 2014
9:42 PM EDT
Thanks for the info penguinist. At 96 dpi, it won't necessarily kick-in by default. That is what my laptop says so it isn't necessarily a problem, but it depends on other factors.

What does your machine return for this? xrdb -query | grep Xft.dpi

Depending on what DE you run can also play a factor. Anyway, I hope LibreOffice 4.2.3 looks good for your screen.

Apr 09, 2014
11:06 PM EDT
keithcu wrote:What does your machine return for this? xrdb -query | grep Xft.dpi

$ xrdb -query |grep Xft.dpi
Xft.dpi:        96

I'm running the Xfce DE and as far as I'm concerned the screen is perfectly behaved in this environment. The fonts are precisely drawn with every pixel in its place. There are no unresolved technical issues for me with fonts or display in general except for the inability to disable the auto-powerdown feature which I reported earlier. I'm still waiting for a response on that from Seiki.

Regarding LibreOffice 4.2.3, as far as I'm concerned it looks identical to what I had on my old 1600x1200 monitors. The physical size of the fonts is about the same as before, it's just that now I can have more documents open simultaneously on this larger work surface. Liberation Serif 12 pt looks quite nice, when reducing the font size down to 6 pt then the characters are extremely tiny but still readable. I respond to screen photo requests if there is some test you would like to try.

I think keith that there will be a difference between your hi-res notebook display and my hi-res large screen display. On your screen it will be necessary to use a larger font size in order to get a correctly sized character. On my hi-res large screen display, the physical size of the fonts is about the same as I had on my previous low-res (and smaller) monitors. So I have no need to change font size, and in fact if LO went into an automatic large font mode it would probably be undesirable in the case of physically large dimensioned screens. What worked on the small low-res monitor works also without modification on the large high-res monitor. Double the screen resolution and at the same time double the screen width and the resulting character size will be unchanged. Am I making sense?

Apr 10, 2014
12:39 PM EDT
Hi Penguinist,

LibreOffice HiDPI mode won't kick in for your screen. But I calculated the DPI of your monitor and I agree that don't want it to.

Thanks for this info. I only have one laptop / OS to test it on so I don't know what will happen and should happen on other hardware.

Apr 10, 2014
3:35 PM EDT
Hi Keithcu, I think we are on the same page on this. I would be curious to know the dpi reports for your 13" hi-res screen.

Apr 10, 2014
10:10 PM EDT
My DPI is 192 for rdb -query, although X reports it is 96 dpi resolution. The monitor itself is actually 276 dpi, but working at 192 dpi looks great.

Dec 14, 2014
5:12 PM EDT
Thanks for the input - I was looking at exactly these monitors for myself to use under linux. Currently I run 6x 1920x1200 displays in eyefinity mode under linux which is great, I wanted to replace them with 3x of these.

Do you use composited desktops? Using kde with kwin compositing or ubuntu with compiz, I have to disable compositing as neither can keep up without causing flickering on my 11520x1200 framebuffer, wondering how even a single 4k display holds up.

Keep up the good work, let us know how your adventures fare with steam or some other gl gaming - really want this more for desktop use, but curious how the amd drivers are.

Dec 14, 2014
10:58 PM EDT
Thank you, mikebutash, for the comments.

One postscript that I can add to my adventure: the native video driver that comes with Fedora 21 now drives this combination directly with acceleration, so there is no longer a need to use the proprietary AMD driver.

Now that I have been using a 39" 4K monitor for nearly eight months, I am still very pleased with this solution. I doubt that I will be going back to those tiny monitors ever again. A couple months ago I bought a second one of these 39 inch 4K monitors so now I have them running at home and at the office. I've found that I can be pretty productive when I have 3840x2160 pixels of space to work with.

Dec 15, 2014
9:27 AM EDT
$ xrdb -query |grep Xft.dpi Xft.dpi: 240

Lenovo Yoga 2 Pro 13.1" laptop, 3200 x 1800

Dec 15, 2014
11:52 AM EDT
number6x: on the Seiki 39" that looks like this:

xrdb -query |grep Xft.dpi
Xft.dpi:	140

Dec 21, 2014
6:12 PM EDT
I'm very interested in this setup, but I read a lot about terrible latency issues. Other reports mentioned that the 4k TVs are not usable as a computer monitor because the latency is so high that the mouse cursor keeps moving noticeably although you stopped the mouse movement already. I did not read about this issue in your post. What is your experience in this regard?

Dec 21, 2014
10:23 PM EDT

Regarding latency, it is essential with 4k TVs that you drive them with a graphics card that is capable of hardware acceleration at the 4k resolution AND that you use a driver that is capable of enabling that hardware acceleration.

When I first attempted to run without hardware acceleration, I noticed the high latency that you refer to. The response time was so slow as to be unusable, but with a good graphics card like the Radeon R7-240 (<$90 at Amazon or Tiger Direct) that I'm using I'm seeing splendid latency performance. The mouse moves as fast as I want it to move and it "stops on a dime". Also, I can grab a window with an app running in it and swing it around the screen in large circular motions, and the response is nearly instantaneous.

As I mentioned, it is important not only to select a good graphics card, but also to back that up with a driver that is capable of enabling its hardware acceleration. In my first experiment, as I detail in the article, the default Fedora 20 driver did NOT enable hardware acceleration. This might be the source of the latency reports you have read. There are two better ways to go. I installed the AMD proprietary linux driver which performed flawlessly with Fedora 20, but since then I notice now that the default driver shipped with Fedora 21 DOES support hardware acceleration on the Radeon card, so it's no longer necessary to use a proprietary driver. I'm guessing that the situation is similar with the other major distributions, but right now my only experience driving this combination is from Fedora.

Having said this, you are limited by the HDMI interface to a 30Hz update rate, but that has just not been an issue with me. Bear in mind that I'm not a gamer, and faster than 30Hz might be more of a careabout if I were, but as a desktop monitor for the kind of development work I do, I couldn't be happier. The 30Hz update rate certainly would not cause the kind of latency you describe. Remember, televisions have been playing fast moving sports programming with 30 HZ updates for decades and few have complained.

You asked a good question, and I hope my response sets your mind at ease a bit. Let me know if you have more questions or would like me to run some specific performance tests on the Seiki/Radeon 4k combination.

Posting in this forum is limited to members of the group: [ForumMods, SITEADMINS, MEMBERS.]

Becoming a member of LXer is easy and free. Join Us!