Table of contents

Background

Ever since I first used a MacBook Pro with Retina display back in 2013, I’ve been madly in love with hi-DPI displays. I had seen the device before, and marvelled at brilliant font quality with which scientific papers would be rendered. But it wasn’t until I had a chance to use the device for a few hours to make i3 compatible with hi-DPI displays that I realized what a difference it makes in the day-to-day life.

Note that when I say “hi-DPI display”, I mean displays with an integer multiple of 96 dpi, for example displays with 192 dpi or 288 dpi. I explain this because some people use the same term to mean “anything more than 96 dpi”.

In other words, some people are looking for many pixels (e.g. running a 32 inch display with 3840x2160 pixels, i.e. 137 dpi, with 100% scaling), whereas I desire crisp/sharp text (i.e. 200% scaling).

Hence, in 2014, I bought the Dell UP2414Q with 3840x2160 on 24" (185 dpi), which was one of the first non-Apple devices to offer a dpi that Apple would market as “Retina”.

After getting the Dell UP2414Q, I replaced all displays in my life with hi-DPI displays one by one. I upgraded my phone, my personal laptop, my work laptop and my monitor at work.

Dell UP3218K

In January 2017, Dell introduced the Dell Ultrasharp UP3218K monitor at the Consumer Electronics Show (CES). It is the world’s first available 8K monitor, meaning it has a resolution of 7680x4320 pixels at a refresh rate of 60 Hz. The display’s dimensions are 698.1mm by 392.7mm (80cm diagonal, or 31.5 inches), meaning the display shows 280 dpi.

While the display was available in the US for quite some time, it took until October 2017 until it became available in Switzerland.

Compatibility

The UP3218K requires connecting two separate DisplayPort 1.4 cables in order to reach the native resolution and refresh rate. When connecting only one cable, you will be limited to a refresh rate of 30 Hz, which is a very noticeable annoyance on any display: you can literally see your mouse cursor lag behind. Ugh.

Note that this mode of connection does not use Multi-Stream Transport (MST), which was a trick that first-generation 4K displays used. Instead, it uses the regular Single-Stream Transport (SST), but two cables.

As of November 2017, only latest-generation graphics cards support DisplayPort 1.4 at all, with e.g. the nVidia GTX 1060 being marketed as “DisplayPort 1.2 Certified, DisplayPort 1.3/1.4 Ready”.

AMD Radeon Pro WX7100

Hence, I thought I would play it safe and buy a graphics card which is explicitly described as compatible with the UP3218K: I ordered an AMD Radeon Pro WX7100.

Unfortunately, I have to report that the WX7100 is only able to drive the monitor at native resolution when using Windows. On Linux, I was limited to 1920x1080 at 60Hz (!) when using the Open Source amdgpu driver. With the Closed Source amdgpu-pro driver, I reached 3840x2160 at 60Hz, which is still not the native resolution. Also, the amdgpu-pro driver is a hassle to install: it requires an older kernel and isn’t packaged well in Debian.

nVidia GeForce GTX 1060

I returned the WX7100 in exchange for the cheapest and most quiet GeForce 10 series card with 2 DisplayPort outputs I could find. My choice was the MSI GeForce GTX 1060 GAMING X 6G (MSI V328-001R). The card seems like overkill, given that I don’t intend to play games on this machine, but lower-end cards all come with at most one DisplayPort output.

Regardless, I am happy with the card. It indeed is silent, and with the Closed Source driver, it powers the UP3218K without any trouble. Notably, it supports RandR 1.5, which I’ll talk about a bit more later.

Compatibility Matrix

Operating System	Graphics Card	Driver	Resolution
Windows	Radeon WX7100	yes	7680x4320 @ 60 Hz
Windows	GeForce 1060	yes	7680x4320 @ 60 Hz
Linux	Radeon WX7100	amdgpu	1920x1080 @ 60 Hz
Linux	Radeon WX7100	pro	3840x2160 @ 60 Hz
Linux	GeForce 1060	nVidia	7680x4320 @ 60 Hz

Recommendation

If you want to play it safe, buy an nVidia card of the GeForce 10 series. Verify that it says “DisplayPort 1.4 Ready”, and that it comes with two DisplayPort outputs.

I read about improvements of the amdgpu driver for the upcoming Linux 4.15, but I don’t know whether that will help with the problems at hand.

Impressions

The unboxing experience is well-designed, and all components make a good impression. All cables which you will need (two DisplayPort cables, a power cable, a USB cable) are included and seem to be of high quality.

The display has a thin bezel, much thinner than my other monitors ViewSonic VX2475Smhl-4K or Dell UP2414Q.

The power LED is white and not too bright. The on-screen menu reacts quickly and is reasonably intuitive.

The built-in USB hub works flawlessy, even with devices which don’t work on my standalone USB3 hub (for reasons which I have yet to find out).

Display Quality

The display quality of the screen is stunningly good.

It was only when I configured 300% scaling that I realized why some Chromebooks had a distinctly different look and feel from other computers I had used: I always assumed they differed in font rendering somehow, but the actual difference is just the screen DPI: fonts look distinctly better with 288 dpi than with 192 dpi, which of course looks better than 96 dpi.

Some people might wonder whether an 8K display is any better than a 4K display, and I now can answer that question with a decisive “yes, one can easily see the difference”. I’m not sure if the difference between a 288 dpi and a 384 dpi display would be visible, but we’ll see when we get there :-).

Glossy

What I didn’t expect is that the UP3218K is a glossy display, as opposed to a matte display. Depending on the brightness and colors, you might see reflections. With my preferred brightness of 50%, I can clearly see reflections when displaying darker colors, e.g. on a black terminal emulator background, or even in my grey Emacs theme.

While one can mentally ignore the reflections after a little while, I still consider the glossyness a mild annoyance. I hope as 8K displays become more prevalent, display vendors will offer matte 8K displays as well.

Scaling

I found it interesting that the display works well in both 200% scaling and 300% scaling.

When running the display at 200% scaling, you get 3840x2160 (4K resolution) “logical pixels”, but sharper.

When running the display at 300% scaling, you get 2560x1440 “logical pixels”, but extremely sharp.

I would say it is a subjective preference which of the two settings to use. Most likely, people who prefer many pixels would run the display at 200%, whereas I prefer the 300% scaling mode for the time being.

Linux compatibility / configuration

To use this display without gross hacks, ensure all relevant components in your software stack support RandR 1.5. My known working configuration is:

• Xorg 1.19.5
• nVidia driver 375.82
• libxcb 1.12
• i3 4.14
• i3lock 2.10

With the following command, you can create a RandR MONITOR object spanning the DisplayPort outputs DP-4 and DP-2:

xrandr --setmonitor up3218k auto DP-4,DP-2

I place this command in my ~/.xsession before starting i3.

Theoretically, Xorg could create a MONITOR object automatically. I filed a feature request for this.

Scaling compatibility

With regards to scaling issues, the situation is very similar to any other monitor which requires scaling. Applications which were updated to support 200% scaling seem to work with 300% scaling just as well.

Of course, applications which were not yet updated to work with scaling look even smaller than on 200% displays, so it becomes more of a nuisance to use them. As far as I can tell, the most likely offender are Java applications such as JDownloader.

Buzzing noise

Unfortunately, the monitor emits a high-pitched buzzing noise, very similar to Coil Whine. The noise is loud enough to prevent focused work without listening to music.

I verified that this symptom was happening with Windows and Linux, on two different computers, with default monitor settings, and even when no input source was connected at all.

Finally, I contacted Dell support about it. In the call I received on the next business day, they were very forthcoming and offered to replace the monitor.

The replacement monitor still emits some noise, but much less pronounced. I think I can easily ignore the noise.

Update after 2+ years: I had honestly forgotten that the replacement monitor also made noise. Maybe it went away, or my ears have gotten worse, or I just didn’t notice for long enough.

Wakeup issues

Rarely (less than once a week), when waking up the monitor from DPMS standby mode, only the left half of the screen would appear on my monitor.

This can be fixed by turning the monitor off and on again.

My theory is that one of the scalers does not manage to synchronize with the video card, but I don’t know for sure.

Interestingly enough, I also encountered this issue with the Dell UP2414Q I bought in 2014. My workaround is to power down that display using its power button in the evenings, and power it up in the mornings.

Update after 2+ years: I have now figured out that the monitor wakes up reliably after:

1. Swapping the cables around at my Graphics Card, i.e. using output DP-4 for the left monitor half and output DP-0 for the right monitor half, not the other way around:

   xrandr \
   --output DP-4 --mode 3840x4320 --panning 0x0+0+0 \
   --output DP-0 --mode 3840x4320 --panning 0x0+3840+0 --right-of DP-4
   

2. When powering on the monitor, waiting until it shows the dialog box “No signal on DP1”, and only then waking up my machine to generate a signal.

When disconnecting and re-connecting the monitor to another machine, I found these steps the most reliable:

1. Power off the monitor, then unplug the two DisplayPort cables.
2. Plug in both cables, then power the monitor on again.
   An easy mistake to make is to not push the DisplayPort connector in all the way. This issue usually manifests itself as the monitor still showing a picture (because the second cable likely is plugged in correctly), but the full resolution not being available.

I have used these two steps twice a workday for weeks on end, and the monitor came up reliably every single time.

Power Usage

When the display is turned on, it consumes about 70W of power.

But, when the display enters “power saving mode”, for example because you ran xset dpms force off, it still consumes 30W of power! Therefore, better turn it off with the button every night, so that it consumes less than 1W.

Conclusion

For me, this monitor is worth it: I am okay with paying the hefty Research & Development tax that first-to-market products such as this monitor have. I like to think that I’m voting with my wallet to make sure vendors notice my interest in “Retina” displays.

For most people, I would recommend to wait until the second or third generation of 8K monitors. By then, I expect most issues to be resolved, compatibility to not be a concern, and vendors focusing on extra features. Hopefully, we’ll eventually see matte 8K monitors with higher refresh rates than 60 Hz.

Technical details

In the hope the following is useful (perhaps for debugging?) to anyone:

• hex dump of the EDID data block
• decoded EDID block
• xrandr --prop output
• Xorg.0.log