4K Monitors: Everything You Need to Know

Josh Norem

Ultra HD (UHD) is the next-gen PC resolution—here’s why you have to have it

Dream Machine 2013 had some bitchin' hardware, but most of it was available at retail for any well-heeled hardware hound. One part, though, was not available to the unwashed masses: its glorious 4K monitor. You see, 4K was an other-worldly resolution back in mid-2013, simply because it offered four times the resolution of 1080p—at a wallet-busting expense of $3,500.

Now, though, 4K is available and relatively affordable, and all modern games support it, making it one hell of an upgrade. Over the next pages, we'll tell you all about 4K, show you what you need to run it at its maximum output, and explore 4K gaming benchmarks, too. But as sweet as it is, it's not for everyone, so read this guide before making the move.

What is 4K?

a slight misnomer, but catchier than ultra hd

To put it simply, 4K doubles the standard 1920x1080 resolution both vertically and horizontally to 3840x2160, which is quadruple the pixels. We can already see you folding your arms and scanning the page for a downvote button, saying, “That’s obviously not true 4K. It only sums up to 3,840 pixels.” “True” 4K resolution is a term used in the movie industry. When you hear about movies being shot in 4K, they’re typically shot at 4096x2160 with an aspect ratio of 17:9. On the PC side, we generally run with television makers, who have mostly settled on a resolution of 3840x2160, which uses the same 16:9 aspect ratio as 1080p. Despite this being far short of 4,000 pixels horizontally, television and monitor makers have all settled on 4K as the term to push, rather than Ultra HD. In other words, we don’t make up the buzzwords, so hate the game, not the player.

In a historical context, 4K is simply the next rest stop along the path of technological progress. Way back in the day, we ran our displays at 640x480, then 800x600, then 1024x768, and then 1280x1024, and so on. As graphics cards became more powerful, we were slowly able to bump up our display resolutions to where they are now, which for a large majority of gamers is 1920x1080, or 1080p. Society has settled on 1080p as the go-to resolution right now, simply because those monitors (and TVs) are very affordable, and you don’t need a $500 graphics card to run today’s games at that resolution.

Not everyone is average, though. Many enthusiasts today run 27-inch or 30-inch monitors at much higher resolutions of 2560x1440 or 2560x1600, respectively. That may seem like a step up from 1920x180, but a GeForce GTX 780 ti or Radeon R9 290X isn’t even stressed  by 2560x1440 gaming. Factor in PCs with multiple GPUs, and you start to wonder why we’ve been stuck with 2560x1600 for more than seven years, as everything else has leapt forward. We won’t question that wisdom, but we do know that it’s time to move forward, and 4K is that next step. Looking ahead, the industry will eventually move to 8K, which quadruples the pixels, and then 12K, and so forth. In fact, some vendors already demonstrated resolutions way beyond 4K at CES 2014, including Nvidia, which ran three 4K panels at 12K using four GTX Titans in SLI. For 2014 and beyond, though, 4K is the new aspirational resolution for every hardcore PC gamer.

It’s All About the Pixels Per Inch

You know how every time we pass around the sun once more and it’s a new year, people joke about their “New Year’s Resolution” being some sort of super-high monitor resolution? Well, we do it, too, because as hardware aficionados there’s always room to grow and new boundaries to push. We want our hard drives to get bigger right alongside our displays, so the move into 4K is something we have been looking forward to for more than a year; as resolution scales up, so does the level of detail that is rendered on the screen. The official term for this spec is pixels per inch, or PPI, and it’s a good bellwether for how much detail you can see on your display.

To see how PPI varies according to screen size, let’s look at a few examples. First, a 24-inch 1920x1080 display sports roughly 91 pixels per inch. If you bump up the vertical resolution to 1,200 pixels (typical on some 16:10 ratio IPS panels), you get a PPI of 94. If you crank things up a notch to 2560x1440 at 27 inches, the PPI goes to 108, which is a small bump of about 20 percent, and probably not very noticeable. Moving on to 2560x1600 on a 30-inch panel, you actually get lower density, arriving at a PPI of 100. To put this in the context of a mobile device, the Google Nexus 5 smartphone has a 4.95-inch display that runs a resolution of 1920x1080, giving it a crazy-high PPI of 445. The iPad’s 9.7-inch screen delivers a PPI of 264, and the iPhone 5’s PPI is 326 pixels. Clearly, there’s a lot of room for improvement on the PC, and 4K is a step in the right direction.

Pixel Peeping

Now, let’s look at the PPI for a few of these fancy new 4K monitors that are coming down the pike. We’ll start with the model we used for Dream Machine 2013 , which is an Asus PQ321Q. With its resolution of 3840x2160 spread across 31.5 luscious inches, its PPI is a decent 140, a noticeable increase from a 2560x1600 display. Not enough for you? Dell has a new 24-inch 4K monitor dubbed the UP2414Q that shrinks your icons for you while retaining their sharpness. Still, it has the highest PPI yet for the desktop panel at a skyscraping 185 pixels. Slightly below the Dell is a new Asus LCD named the PB287Q, which at 28 inches has a modest PPI of 157 pixels. Keep in mind that in some cases, this is a 50 percent increase in the number of pixels per inch, so when you tally that up across the entirety of the display, it equals quite a few more pixels, which results in a lot more detail that is visible even to the naked and semi-clothed eye.

Why it’s a big deal

Just like going from a 24-inch 1080p monitor to a 30-inch 1600p monitor is a life-changing experience, so is going to a 32-inch or smaller 4K panel. The level of detail you can see on the screen is surprising, and when you fire up Battlefield 4 for the first time, you’ll most likely be staring at the screen with your mouth open, and not just because the server dropped you again. Gaming at 4K looks simply incredible. And unlike television, where there’s a dearth of content, almost all PC games support the resolution, and some developers are even including higher resolution textures now, too.

Of course, both Nvidia and AMD are also pushing 4K because you need one hell of a GPU setup to push those pixels around. Since 4K is still extremely new and not quite ready for prime time, the hardware required to run it is in the same embryonic stage, which translates in layman’s terms to “almost there but not quite.”  Even a GeForce GTX Titan with its 6GB frame buffer or a Radeon R9 290X and its 4GB frame buffer can barely eclipse 30fps at 4K with all settings maxed. Sure, you can turn down some of the settings and get a flagship GPU to run pretty well at 4K these days, but we’d rather castrate ourselves with a soldering iron than turn down the eye candy. We didn’t spend $3,500 on a monitor, or have our friends die face-down in the muck, to turn down graphics settings, so we’re not budging on that. With all settings turned up, gaming at 4K is truly cutting-edge, and is really the only application that currently stresses today’s crop of high-end GPUs, aside from a multi-monitor setup. Today, getting any single GPU to run 4K at the magical 60fps is not possible. There’s even a telling statement on the Nvidia website: “In order to power games at this resolution (4K) with settings turned up, NVIDIA recommends GTX 780 SLI or better.”

Is 4K 'Retina'?

First off, you have got some balls to compare a glorious 4K display to a marketing term such as "retina display." However, for the sake of argument, we'll humor you. As noted elsewhere, a 4K display can have as many as 185 pixels per inch (PPI), which is almost double what is found in today's 1080p displays. However, the term "Retina" as coined by The Jobs is usually more than 200 PPI for a notebook, and more than 300 for a mobile display. You see, a PPI rating's significance all comes down to how close you are to the display. Apple defines a Retina display as having enough pixels that the human retina can't distinguish between them, which is quite easy to pull off at a distance of 16 inches, but much less so at six inches.  Therefore, mobile displays, which are held closer to your face, oftentimes have crazy-high PPI ratings. Interestingly, despite being the first to heavily push high-PPI displays, Apple has been out-Retina’d these days. The Samsung Galaxy S4 has a PPI of 441 PPI, and the Sony Vivo Xplay sits at an insane 490 PPI. The iPhone, with its rating of 326, actually isn't even in the top ten of high-PPI devices. Still, if you ask the average Joe, he’ll say Retina is better. The bottom line: At a far enough distance, everything is a retina display, because pixels are indistinguishable.

Go Big or Go Home

Full HD, Ultra HD, HD HD—what does it all mean?

HD 720p

A resolution with more than 700 horizontal pixels was the original “HD” resolution and was used to sell a zillion television sets the world over. On a 1600x900 20-inch display, you get a reasonable PPI of 92.

Full HD 1080p

After vanilla HD came Full HD, which cranked it up a notch to 1920x1080 resolution. Full HD is just a marketing term, though, as there’s no HD-sanctioning body. Full HD on a 23-inch panel delivers a PPI of 96, so, not much better than HD.

Quad HD

Though usually not referred to by its proper name, Quad HD refers to a panel featuring 2560x1440 resolution, which is four times the pixels of HD. A 27-inch panel at this res features a so-so PPI of 108.

Ultra HD

This is actual 4K resolution, meaning 4,000 horizontal pixels. It is four times the resolution of Full HD, and features a PPI of 144 pixels on a 32-inch panel. The term refers to how professional film is produced and projected though, so it’s not really a PC term since PC displays are slightly less than 4K at 3840x2160.

4K confusion cleared up

How to pick the right 4K monitor

It used to be easy to pick a monitor when your biggest decision was choosing between an IPS or TN panel, and your choice at the high end was either 24 or 30 inches. Today, it isn’t so easy. Besides the thorny question of whether to choose an IPS model for its superior color accuracy and off-axis viewing or going with a speedier TN panel, you now have to factor in very high refresh rates, pixel density, resolution differences, and even such technology as Nvidia’s new G-sync. We can’t pick for you, but we can help you make your decision.

As with all things in computing, there is no one-size-fits-all product. How much monitor you need depends on your specific usage. Are you a gamer? A content creator? A multi-tasker? On a budget, or a baller like Carlos Slim?

For a professional or advanced amateur editing photos or video, the color accuracy of TN panels still isn’t good enough. Today’s budget 4K panels, such as Dell’s $699 P2815Q or Asus’s $799 PB287Q, both use TN panels, so pixel peepers will want to move along. The Dell P2815Q also features a major flaw in that its refresh rate is limited to 30Hz at its native resolution. For professionals, the only real answer for now is to go big (and expensive) with the Asus 32-inch PQ321Q for $3,000, or go dense with the 24-inch Dell UP2414Q for $1,300. The Asus model uses an IPS panel from Sharp with indium gallium zinc oxide (IGZO) to help it pack the pixels so closely. The Dell is also an IPS panel, but other details of the panel technology have yet to be disclosed. Both will hit 60Hz, but you’d better have a gnarly GPU or two if you want to use these panels for gaming. The Dell’s pixel density is to die for, with 183 pixels per inch. That’s about double that of a standard 24-inch 1920x1080 panel. There are PC panels that are denser, but not in a desktop form factor. Remember: You’ll need bionic vision, too, if you intend to use these monitors without scaling cranked up a few notches, because windows and icons will look like miniatures—and we’re not happy with how Windows scales up right now.

That brings us to the refresh rate debate. For gamers, 60Hz IPS or TN panels are OK, but if you’ve ever played on a 120Hz panel with a powerful GPU pushing it, you know just how beautifully blur-free they can be. We dare say it, if we gamed more than we edited photos or videos, we’d take a pass on the lowly 60Hz panels. The problem with high-refresh monitors has been their pedestrian resolution of 1920x1080 in 24 inches. There are 120Hz 27-inch monitors as well, but their 1920x1080 resolution gives them a remarkably low pixel density of just 81 PPI. Asus thinks it has the gamer’s ultimate fantasy monitor with its new ROG Swift PG278Q. This 27-inch TN monitor has a respectable resolution of 2560x1440 and a refresh rate of 120Hz. While its pixel density doesn’t approach that of a 4K monitor, the 120Hz refresh may compensate for gaming purposes—for those with hefty GPUs.

For those with lesser graphics cards, though, the Asus Swift monitor also boasts Nvidia’s new proprietary G-sync technology. (The Titan, 7-series, and several 6-series are supported in G-sync.) This tech syncs the monitor’s refresh rate to the GPU’s rendering, translating to smoother and sharper images, even if the frame rate dips below 30fps. G-sync, of course, won’t work with AMD cards, but for gamers not hung up on color accuracy or off-axis viewing, the ROG Swift might be the ultimate monitor right now in the green camp. And yes, we know AMD has talked of FreeSync—the free method to sync refresh with GPU rendering. It’s just not clear if FreeSync will work with desktop monitors yet, although it is promising on laptops, which are typically fairly low-powered in the graphics department.

The Asus ROG Swift is the first 2560p monitor with a 120Hz refresh rate.

What about a 120Hz panel that also runs at 4K? That’s coming too, but remember that you’ll need an inordinate amount of graphics grunt to push twice the pixels of a single 4K panel.

What you'll need to run 4K

We hope you got a huge tax refund

You'll need new cables

If you're like us and have been running DVI or dual-link DVI for the past—oh, we don't know, forever?—4K requires a different connection, as the Digital Visual interface tops out at 2560x1600 at 60Hz—far short of 4K’s needs. To run 4K resolution, you will need to run either DisplayPort 1.2 or HDMI 2.0. For those on the DisplayPort train, version 1.2 is available today and will let you run 4K at 60Hz when using a Multi-Stream Transport (MST) mode. In MST mode, the graphics card generates several signals, or "streams," which are combined over the DisplayPort cable in order to run the panel at 60Hz. If you were to use a DisplayPort cable and run the panel in Single Stream Transport (SST) mode, you would top out at 30Hz. If you're more interested in running HDMI for some reason, it’s more complicated. A single HDMI 1.4 connection is only able to hit 30Hz at 4K resolution, which is unacceptable. Some posters on our website have said "30Hz is fine for porn and web browsing," but we disagree. Just dragging a window around the screen causes it to shear and stutter in a manner similar to how it looks when you run your PC without graphics drivers installed. Some monitors and GPUs allow dual-HDMI connections to achieve the bandwidth needed, but it’s a kludge and few support it. The fix for HDMI will come with HDMI 2.0, which will easily allow 60Hz at 4K, as well as multi-channel audio, but no monitor nor any GPU we know of currently has the new interface. So, be sure to verify what your panel supports before buying; if you get a 30Hz panel, you will be very, very sorry. And forget about trying to game on that thing.

The monitors

We're still in the beginning stages of 4K monitor growth. Throughout the year, you should see 4K panels offered from all the usual suspects. The good news is that prices have already dropped from the $3,500 mark down to under $1,000, and we expect many more manufacturers to be offering panels in this lower price range. Whether or not we'll get an affordable 4K IPS panel is a different story. Although, for gaming, TN is fine. The Dell 24-inch IPS panel is relatively affordable at $1,299—just don't expect to see it hit the $500ish prices of today's 27-inch and 30-inch panels until at least 2015, if not later.

The GPUs

If you thought purchasing a 4K monitor was financially painful, you ain't seen nothing yet. That transaction was merely foreplay for the real pain and suffering that will occur when you have to buy enough graphics firepower to run that display at its native resolution on today's games. As we stated earlier, Nvidia itself recommends at least two GTX 780 cards in SLI, so that's $1,000 worth of GPU, on top of the $800 to $3,500 for the monitor. The cheapest way to get into the 4K ballgame at this point would be to buy two Radeon R9 290 cards—assuming you can even find them for sale anywhere—which will set you back $800. Or you could get two GTX 780s, which will cost you roughly $1,000. You can pretty much forget about anything less powerful than these $400 to $500 GPUs though, as we can guarantee you they won't pack enough of a punch to drive a 4K display to anywhere close to 60Hz. Even the last generation of dual-GPU boards, such as the GTX 690 and Radeon HD 7990, aren’t up to the ask on their own.

In most cases, the price of a 4K monitor will pale in comparison to the GPUs needed to game on it.

4K benchmarks

Before you look at the benchmark chart below, we recommend that you walk over to your PC and put a blanket over it. Seriously, it doesn't want to see you staring at these benchmark numbers. When you see how incompetent even the most high-end GPUs on the planet are for running 4K, it will probably make your PC seem, well, inadequate. What we mean is, look at these numbers. Even a $700 GeForce GTX 780 Ti can only hit 23fps in Unigine Heaven 4.0 with everything maxed out, and it hits only 19fps in Metro: Last Light. If there's one takeaway from this benchmark chart, it's this: Most of today's high-end GPUs are still not capable of running 4K at an acceptable level of performance. We're sorry, but that is a fact. Sure, all these games are playable—some more than others—but none of these cards, or combinations thereof, could hit 60fps in any of the games we chose for benchmarking. For this generation of GPUs, this is the reality.

Since 4K is gaining so much traction, it's very likely that whatever is coming from AMD and Nvidia will be better equipped to handle this resolution, and we certainly hope it is.

We've heard nothing about what AMD has up its sleeve, as we expect its Hawaii cards to have a long shelf life. The impending Mantle API update should give the cards a shot in the arm, so to speak. As with Nvidia, though, the current generation is barely capable of running 4K, so we can expect the next-generation cards to be much more capable. The good news is that by the time these newfangled cards arrive, we should have a whole flock of new 4K panels on offer, so it'll be glorious times for well-heeled PC gamers.

Nvidia GTX 780 Ti
Nvidia GTX 780
Nvidia GTX Titan AMD Radeon R9 290X AMD Radeon R9 290X Crossfire Nvidia GTX Titan SLI EVGA GTX 780 ACX SLI
332.21 13.12 13.12 332.21 332.21
Unigine Heaven 4.0 (fps) 23 23
21 18 17 37 30
Unigine Valley 1.0 (fps)
28 26 23 37 16
Tomb Raider (fps) 28
25 27 52 44 44
Metro: Last Light (fps)
19 17
17 18 29 26 26
Battlefield 4 (fps) 40 36
35 38 64 60 57
Batman: Arkham Origins (fps) 44 43 41 38 66 57 57
Hitman: Absolution (fps) 44 39 40 44 75 55 55

Best scores are bolded. Our test bed is a 3.33GHz Core i7 3960X Extreme Edition in an Asus Rampage IV Extreme motherboard with 16GB of DDR3/1600 and a Thermaltake ToughPower 1,050W PSU. The OS is 64-bit Windows 8. Our monitor is a 32-inch Sharp PN-K321. All games are run at 3840x2160 with no AA.

Around the web