Hardware Compatibility, Dual-Scaler Design and Potential Issues
Is It "Retina"?
At 140 PPI, if you sit at least 25 inches from the UP3214Q, it meets the street definition what a Retina display should be. The 24-inch model (~187 PPI) fits even more comfortably into that category.
Retina is a marketing term Apple uses to designate its high-PPI displays. The idea behind Retina is this: with a high enough pixel density, users should be unable to discern individual pixels at typical viewing distances. Of course, visual acuity and typical viewing distances can vary greatly, so what constitutes a Retina display is open to some interpretation. Check out this article from DisplayMate for an interesting look into why Retina falls short of being an exact standard.
Note, there is no minimum PPI requirement to be Retina. For example, an iPhone 5 (326 PPI) and Retina Macbook Pro (~240 PPI) are both considered Retina because they are used at different distances. The further away you view a display, the harder it is to discern discrete pixels. At 140 PPI, 25 inches is the minimum distance where this should be true for someone with 20/20 vision. As it happens, Im sitting about 30 inches from this monitor as I type.
The UP3214Q is kind of the full-size SUV of displays, at least where guzzling power is concerned. According to some quick Kill-A-Watt readings, Dells 4K flagship sucks anywhere between 55 (lowest brightness) to 103 watts (maximum brightness). By comparison, a 27-inch UltraSharp U2713HM (2560 x 1440p IPS) at maximum brightness hits a paltry 50 watts.
Hardware Compatibility and The Horrors of 30Hz
In short, owners need a modern DisplayPort output (1.2 or better) or Thunderbolt 2.0. The UltraSharp UP3214Q doesnt have Thunderbolt per se, but Thunderbolt is physically and electrically compatible with mini-DisplayPort 1.2.
The display does provide an HDMI hook up, but its only HDMI 1.4. The best HDMI 1.4 can deliver is 3840 x 2160p @ 30Hz and trust me, you dont want 30Hz. After using 30Hz for much longer than I care to remember, I cant believe that 30Hz 4K monitors actually exist. Why anyone would ever make this compromise, Ill never understand. At 30Hz, every action performed (e.g. opening menus, scrolling web pages, moving the mouse around) felt distractingly slow and unresponsive. I couldnt acclimate to it, so I happily switched back to DisplayPort.
Excluding overhead, 3840 x 2160 pixels with 10-bit/channel color @ 60Hz requires a whopping 16Gb/sec of bandwidth. The only standards capable of meeting this demand are DisplayPort 1.2, HDMI 2.0 (just barely) and Thunderbolt 2.0. Although DisplayPort 1.2 arrived in 2009 doubling the bandwidth of DP 1.1, the last two standards didnt hit the scene until just recently. In a nutshell, the only connection on the UP3214Q capable of supporting 60Hz is DisplayPort. Alas, VGA (9.63 Gbit/s) and Dual-DVI (8.16 Gbit/s) are officially obsolete.
Most of my review time was split between a lower-end Radeon HD 7770 and much higher-end Geforce GTX 770. The Radeon was able to drive the UP3214Q at its native resolution and at 60Hz via DisplayPort, but I had to enable this manually on the graphics driver. By default, DisplayPort 1.2 is disabled, presumably for maximum compatibility out of the box. With DisplayPort 1.2 toggled off though, the panel operates at 30Hz instead of 60Hz and as I can attest, the results are overtly painful.
Dual-Scaler Design: The Source of Many Problems
Ive been told that in order to deliver a 60Hz refresh rate, manufacturers have designed their displays to act as two separate 1920 x 2160p panels. Known as a tiling, this method leverages MST (multi-stream transport) to work around DP limitations which would otherwise prevent 30-bit 4K @ 60Hz. To the best of my knowledge, all current 60Hz-capable 4K UHD computer displays feature a tiled design. The ones that arent tiled are 30Hz and if theres is one thing you should remember today, I hope, its how utterly revolting 30Hz is.
Because the UP3214Q is treated like two panels seamlessly stitched together, the display has the capacity of behaving rather strangely. Special graphics driver support is required for tiled displays to operate flawlessly, which I understand is slightly more involved than just consumer dual-head support (e.g. automatic spatial placement, frame buffer synchronization, updated EDID support). Its clear that 4K support is still a work in progress for driver makers though. Some examples include Nvidia only recently solving its uneven screen tearing issue, while AMD just added 3840 x 2160p auto-detection in November.
With our three test cards (GeForce GTX 770, GeForce GTX 660, Radeon HD 7770), some unintentional behaviors occasionally cropped up. These issues include anomalous split screens, half-screen images, not waking up from sleep and even a few random moments where output was randomly (but very briefly) interrupted. The primary agitator seems to be power state changes (i.e. standby), but they also appeared after changes in input (e.g. swapping video cables, selecting different input sources, switching test systems) and resolutions (e.g. gaming). In all of these situations though, powering off the display and turning it back on was the quick fix.
It seems reasonable to assume these are merely software problems. Unfortunately, these problems occurred even with the latest WHQL and beta drivers available. If you buy a 4K monitor today, expect some quirks. I remain hopeful though that this will improve in the very near future.
Not to make excuses, but it feels a bit like Dells UP3214Q is really a victim of marginal input standards and imperfect drivers. Ahead of its time? Perhaps. The good news is DisplayPort 1.3 promises single-stream 4K @ 60Hz, but that ship isnt scheduled to sail until later this year. I should point out that this will also not help the UP3214Q as its DisplayPort 1.2 and HDMI 1.4 ports are a permanent feature. Interestingly though, tiled 4K displays may prove to be a very brief, historical blip. Hopefully, so will 30Hz displays.