Gaming and Other Challenges, DPI Scaling
Lack of Resolutions
One of the most obvious limitations of display tiling is a lack of viable resolutions. Because we're dealing with essentially two screens, common 16:9 resolutions like 2560 x 1440p, 1600 x 900p and even 1920 x 1080p are either missing (Radeon) or don't fill the screen (Nvidia). If you're a gamer but haven't made a significant investment in 4K UHD gaming, then tiled 4K displays are not for you.
With a modest Radeon HD 7770, there was an absence of lower resolutions. Even with the latest Catalyst drivers (13.11 and 13.12) and the latest Dell monitor drivers/software installed, only the following oddball resolutions were available: 1920x2160, 1856x1392, 1800x1440, 1792x1344 and 1152x864.
Unlike the lower-end Radeon HD 7770, our GeForce GTX 660 and GTX 770 offered a variety of 16:9 resolutions; however, making use of them was a different matter. Regardless of panel scaling options, the UP3214Q would not fill the screen at lower resolutions. For example, at 1920 x 1080, the image occupied only a tiny portion of the screen's center. This is an unfortunate limitation of tiling.
Mac Compatibility
We might be PC enthusiasts at TechSpot, but we'd be remiss to not touch on Apple products from to time. Although a number of Macs sport hardware capable of delivering 2160p, the necessary software support isn't quite there. Our Retina MacBook Pro (Late 2013) was able to hit 3840 x 2160p, but it could only do so at 30Hz. Unfortunately, it was not possible to manually increase the refresh rate. As mentioned earlier, 30Hz is worse than a double shot of Malört.
This lack of 60Hz support is interesting since the Retina MacBook Pro in question features Thunderbolt 2.0 (i.e. DisplayPort 1.2), an Intel Iris Pro 5200 (4K ready), an Nvidia GT 750M (also 4K ready) and the latest iteration of Mac OS X Mavericks. At the time of this review, Apple stated the only system capable of 2160p @ 60Hz is its brand new Mac Pro – you know, the one that some believe looks like a trash can. Since the limitation appears to be software, it's likely this will change in the near future. Presumably, all devices equipped with Thunderbolt 2.0 will make the cut.
Gaming
We all know gaming can be an expensive endeavor, but 4K takes that fact and multiplies it by three. Gaming at 4K UHD simply can't be done – especially done well – without a very high-end setup. As a result, most working-class gamers can forget about UHD all together until cheaper hardware becomes available. Okay then, no need to sweat it, right? We'll just kick down the resolution to 1440p or even 1080p. Problem solved... except, as mentioned earlier, these 4K tiled monitors don't operate that way. It's 3840 x 2160p or bust.
Armed with a $350 GeForce GTX 770, most recent games weren't playable unless graphics settings were set to "very low" with MSAA/FSAA judiciously disabled. I probably don't have to tell you how the GTX 660 and HD 7770 fared, but I will anyway: very badly. Even so, doubling or even tripling up on some GTX 770s should make gaming respectable again. Of course, if you're already rocking a thousand dollar 512-bit GPU (i.e. GeForce GTX Titan), you're probably safe for now. One percenters, rejoice.
DPI Scaling
Without DPI scaling, comparing one 27-inch 1080p display against a 27-inch 2160p model reveals a stark difference: graphics and text on the 2160p display will only be half as wide and half as tall. That's only 25-percent of the other's size. This is a natural byproduct of having four times as many pixels crammed into the same amount of physical space on your screen. The plus side of this is a vastly increased workspace area (i.e. desktop). The negative side though is every on-screen graphic, font and button is significantly smaller.
To combat this, DPI scaling enlarges fonts and graphical user interface elements to maintain their "normal" size even at insanely high resolutions (e.g. 2048 x 1536 on a 9.7-inch iPad screen). Although these elements occupy the same amount of screen space, they are more pixel-dense and contain more visual detail. This is the basis for Apple's "Retina" display and various other higher-end screens found in a growing number of devices.
Because of DPI scaling though, UHD-capable computer displays presently suffer a bitter irony. Monitors like these are the ultimate in visual fidelity; however, most third party applications remain ill-equipped to make use of those extra pixels and don't pristinely scale. That means for everyday use, ultra high-definition monitors actually net owners the opposite of what they are trying to achieve.
View the same content on your five year-old 1080p monitor and those items are nicely sized and sharply displayed. Yes, 4K monitor owners can ignore DPI scaling to maintain their crisp image, but even with an expansive 32-inch screen and 20/20 vision, 3840 x 2160p without DPI scaling is plenty uncomfortable.
Websites in general have been designed for common resolutions (1080p @ ~75 PPI). With a 140 PPI monitor, these graphics become half their intended size (unscaled). However due to the availability of high DPI devices, mostly tablets and smartphones and a very limited number of laptops, web graphics are now better optimized for HiDPI displays. In this respect Windows is a year or so late in receiving the special hardware treatment and thus it tends to suffer in terms of third party software compatibility.