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ASUS PQ321 Ultra HD 4K 31.5-inch Monitor Review
Date: Aug 01, 2013
Author: Paul Lilly
Introduction & Specifications
We have a confession to make (well, several actually, but all the rest date back to our college days, and some secrets are best left untold). Reviewing monitors isn't as fun as it once was. It's not that we've grown jaded over the years, but plain and simple, the monitor market has become stale, lacking the kind of 'gee-whiz' innovations that tend to excite us. Panel makers seemed to stopped pushing the envelope once they developed 30-inch In-Plane Switching (IPS) screens, and for the longest time, that's where the high-end has sector been stuck, as if caught in quicksand with no rope in sight, or so we thought.

Out of all the monitor manufacturers out there, it was ASUS that showed up to the panel party with rope in hand, marching through the muck and mire tugging the first consumer 4K display ahead of the competition. And for adding bragging rights, the ASUS PQ321 True 4K Ultra HD measures a just a little bit bigger than current flagship models with a 31.5-inch LED backlit panel, giving monitor enthusiasts yet another reason to upgrade.

Not that the PQ321 is lacking a sales pitch. Boasting a 3840x2160 display resolution, this 4K display floods your eyeballs without four times as many pixels as that of a standard Full HD 1080p (1920x1080) display. To squeeze that many pixels into a 31.5-inch form factor, the PQ321 uses what's called Indium Gallium Zinc Oxide (IGZO) rather than traditional amorphous silicon for the active layer of its LCD panel. IGZO supports much smaller transistors, which in turn paves the way for greater pixel density (and other benefits).

ASUS PQ321 - world's first consumer 4K monitor

So, what can you do with over 8 million pixels at your disposal? Put simply, you can do everything with the PQ321 that you can on lower resolution monitors, only with more detail and a larger workspace, depending on the application. There are some downsides to current 4K technology though -- the refresh rate is capped at 60Hz and it can be a little tricky to setup/configure -- but there is also plenty of upside, especially for professional photographers and graphic artists who demand a high level of detail. We'll cover both ends of the spectrum, but before we do that, let's have a look at the spec sheet.

ASUS 31.5-inch PQ321 4K Ultra HD Monitor
Specifications & Features
Display Size
31.5-inch IGZO
3840 x 2160
Aspect Ratio     
350 cd/m2 
Contrast Ratio 
Response Time
8ms (Gray to Gray)
Viewing Angle
176° vertical / 176° horizontal
Display Type
IGZO (Indium Gallium Zinc Oxide)
2 x HDMI; DisplayPort; RS-232C; 3.5mm mini-jack
Power Consumption 
93W (Typical); <6W (Power Saving); <1W (Power Off Mode)
2 x 2W stereo RMS speakers
Tilt (+25 degrees to 5 degrees); Swivel; Height
I/O Ports N/A
Dimensions (with stand)
750 mm x 489 mm x 256 mm (HxWxD) / 29.5 inches x 19.2 inches x 10.1 inches
13 kg / 28.7 lbs
Included Accessories

Cable clamp; power cord; power adapter; DisplayPort cable; Warranty card; RS-232C conversion cable; Setup manual
3 years casing; 3 years panel; 1 year parts and accessories (optional)
Price $3,499 street

There are couple of things in the spec sheet that we'll play close attention to in this review. The response time, for one, is bit higher than we're used to seeing, and the contrast ratio (typical) is a little lower than most panels. At the same time, bear in mind that monitor specs are general guidelines at best. There are different ways to measure a monitor's performance, making it relatively easy for monitor makers to fudge the numbers if they're so inclined, so we don't put a ton of stock in them to begin with.

The elephant in the room is the price. At $3,499 street, the PQ321 carries a premium price tag that was once occupied by 30-inch IPS panels not that long ago (some still hover in that range). Expect 4K monitors to come down in price once they become more commonplace, but for now, there's a premium attached for being an early adopter.
At 31.5 inches, this is the biggest monitor we've ever reviewed, though it really doesn't appear any more massive than the crop of 30-inch panels we've tested. Be advised when unboxing that the PQ321 is pretty hefty. Fully assembled -- with the base screwed onto the back of the panel -- the entire frame weighs just over 28.6 pounds.

If this is your first foray into 30-inch territory, be prepared to give up some desk space. With the stand attached, the PQ321 measures 750 mm (W) by 489 mm (H) by 256 mm (D), or 29.5 inches (W) by 19.2 inches (H) by 10.1 inches (D). That's something to consider if you picked up a tiny desk for a cramped studio apartment or dorm room. It's not that a 31.5-inch panel can't exist in such an environment, you just might need to upgrade the platform you plan to drop it on.

As far as large size monitors go, however, we were pleasantly surprised with how thin the PQ321 is. It's a far slimmer design than Dell's U3011, the latter of which appears chunky by comparison. If you're so inclined, you can mount the PQ321 to the wall using the VESA mounts on the back of the panel.

Beyond the physical dimensions, the PQ321 gets its 4K mojo by way of an anti-glare, Indium Gallium Zinc Oxide (IGZO) panel developed by Sharp. The anti-glare material works well, and even in direct sunlight, the panel doesn't give off much of a reflection. The IGZO panel is a 10-bit RGB part with a 0.182 mm pixel pitch, 350 cd/m2 brightness, 800:1 contrast ratio, and 8ms response time (gray-to-gray).

If you've never heard of IGZO before, that's because it's a relatively new technology in the consumer segment. Sharp began volume producing IGZO panels a year ago, as there are many benefits in the technology. Electrons move more swiftly in IGZO, allowing for smaller transistors, which in turn lead to smaller pixels. The end of this domino effect is greater pixel density, though there are other benefits, such as lower power consumption and less interference from nearby components for more accurate touch panels. The PQ321 isn't touch-capable, but it does boast a 4K resolution of 3840x2160.

If you're facing the PQ321, all of the input options are located on the left-hand side in a cutout section of the backside, each one clearly labeled on the panel's chassis. The placement is far more convenient compared to monitors that shove the inputs on the underside of the panel, which are often difficult to access as you fumble around with cables hoping to make a connection.

From top to bottom, you'll find the panel's RS-232C input terminal for serial devices (you can't see the port in the picture above due to the shadow), two HDMI ports, and a DisplayPort 1.2 input that's configured for single-stream transport (SST) by default. The panel is capable of running at 60Hz, however, you'll need to switch the setting to multi-stream transport (MST) to do so, a feature we'll cover in a little bit.

On the other side of the panel is a main power switch, AC input terminal, and Kensington lock port. It takes an external power brick to supply the necessary juice for the PQ321, and when plugged in, ASUS claims it consumes around 93W of power (typical).

Much of the monitor's weight is contained in the base and stand. It's a study setup with a decorative flair that offers stability and a bit of ergonomics without an excessive footprint. When we stated earlier that you'll want to make sure your desk will comfortably accommodate the PQ321, we were mainly talking about the size of the panel, and not the stand.

Adjustments include:
  • Tilt: +25 degrees to around -5 degrees
  • Swivel: +45 degrees to around -45 degrees
  • Height: 0 to around 150 mm

Unfortunately the panel's base doesn't allow simple rotation into portrait mode, a sad omission when you're investing $3,500 into a display.  You have to unmount the panel from the stand and then re-mount it in portrait orientation, though it can be done with some elbow grease.

Our final shot shows just how slim the panel is. The PQ321 doesn't rival the slimmest LED monitors on the market, but when pitted against large-size panels, it's clearly at the front of the class. And while the category is new, the PQ321 is still the thinnest 4K Ultra HD monitor out there.

Setup & Configuration
Most monitors are easy to setup. You plug in the power cord, attach the panel to your system via HDMI, DVI, VGA, or DisplayPort, and off you go. That's sort of the case with the PQ321 as well, though at this early stage, it takes a bit of finagling to run the monitor at 60Hz instead of 30Hz.

Trust us when we say you don't want to dink around Windows at 30Hz. There's too much input lag, resulting in a jittery mouse on the desktop, and things are even worse if you intend on gaming. It's a whole new world at 60Hz, and it's made possible here through a combination of video card drivers, monitor settings, and the right connection.

The steps are slightly different depending on which graphics card you own, and the one we'll walk you through is for an AMD 7000 Series GPU (if you own an NVIDIA or Intel Haswell CPU with integrated graphics, you can skip to the embedded video below for detailed instructions).

To run the PQ321 at its native 3840x2160 resolution at 60Hz, you can either use a single DisplayPort 1.2 cable or multiple HDMI cables (all HDMI cables should be connected to a single GPU). ASUS recommends the former and that's how we conducted our testing. In our case, our XFX Radeon HD 7970 Black Edition graphics card has a mini DisplayPort connector, so even though ASUS includes a DisplayPort cable, we had to pick up an adapter.

If you haven't already, be sure to update your AMD Catalyst software to the latest available. When you connect the PQ321 to your system, it's going to default to 30Hz. The first step to changing that is to open up the On Screen Display (OSD) controls and select Setup > DisplayPort STREAM. Change this from SST (single stream transport) to MST (multi-stream transport), save the settings, and hang tight a moment while the monitor reboots.

The screen may look a little funky after the monitor comes back on with multiple taskbar icons and other oddities. That's okay. Proceed to the next step, which is to open the Catalyst Control Panel, expand the AMD Eyefinity Multi-Display option from the left-hand column, and select Create Eyefinity Display Group.

You should see two square boxes labeled 1 and 2. Click on 1 and press Continue. You now need to select a layout for the display group. Select the 2x1 configuration from the pull-down menu and you're golden with a 3840x2160 resolution at 60Hz.

For detailed instructions on how to configure the monitor on all three platforms (AMD, NVIDIA, and Intel's Haswell), ASUS put together a handy video, which we've embedded below:

If this all seems a bit complicated, don't fret, it's really a quick process when you have the monitor in front of you. However, it is a bit annoying to jump through these hoops, though ASUS tells us they won't always be there.

"A multi-stream 4K Display VESA standard is now being finalized, which ASUS will implement in a firmware update of our monitor via USB. This will enable a superior experience on this monitor similar to what users see on existing lower resolution displays without any additional configuration," ASUS says.

What that means is that once there's a standard in place and the monitor's been updated, drivers will recognize when a 4K display has MST enabled and auto-configure itself. It will be just like hooking up any other monitor.
Calibration & Controls
As with most monitors, you can select from a handful of preset configurations. We tested the PQ321 using the Standard profile and with the settings it shipped with from the factory.

Big kudos to ASUS for going against the grain and keeping it old-school with physical buttons. We've never been big fans of touch-sensitive controls, which often fail to register finger taps, especially when you're rapidly scrolling through menus. Physical buttons are also easier to navigate without looking at the controls.

Should you need to look at them anyway, the buttons are on the edge around the back and out of sight. However, ASUS thoughtfully bundles a sticker that you can place on the front bezel next to the buttons with labels corresponding to each one. It's unobtrusive, and totally optional.

ASUS provides several fairly basic settings to tinker with, along with a few advanced options, though we've seen monitors that offer more fine grain control than this one. The upside to the limited number of options is that it's nearly impossible to get lost navigating the menus.
    Professional photographers and graphics artists may want to spend a little time fine-tuning everything, but to our eyes, the PQ321 shipped from the factory needing very little calibration. About the only time we needed to duck our head into the OSD controls was to adjust the input settings, namely the DisplayPort configuration as outlined on the previous page. You can also configure the HDMI ports to work together to form a single image, or work independently of one another.

    Calibration (DisplayMate)
    Menus and Options
    DisplayMate Test Screens

    We're now using DisplayMate for Windows (www.displaymate.com) as part of our monitor evaluation process. DisplayMate's smorgasbord of tests allow us to root out potential problems areas, such as geometry distortion and color inaccuracies, to name just two.

    Since this was our first time spending any significant time with an IGZO display, we didn't know quite what to expect, and so we were pleasantly surprised not to run into any major issues, or very many minor ones for that matter. Slim panels sometimes suffer from color uniformity issues, but that was a strong point of the PQ321. There weren't any splotches of light or color, nor did we discover any other abnormalities, like geometry issues or light bleed through.

    As we've seen in other high-end displays, the PQ321 experienced a slight bit of overshoot in the video bandwidth test. A perfect score in this test is 100, and the PQ321 notched around 104. Overshooting in this test can be indicative of over-peaking and compensation, but that's not something we saw when looking at photos or watching movies.

    Overall, images look great on the PQ321, though not quite stunning, at least not at first. The first time you fire up a true 4K image on the PQ321, though, is not a moment you'll soon forget. Suddenly, the monitor springs to life and you begin to see what all the fuss is about. Colors spring to life with enhanced detail; it's like night and day viewing the the same image on the PQ321 and another monitor.

    There's also the advantage of being able to see more of a particular image. To demonstrate the effect, the scaled down pictures above represent an example of the how a 4K photo (left) compares to the same photo when viewed on a 1080p display (right) without downsizing.
    Subjective Analysis
    While DisplayMate lays out a monitor's performance in black and white (and blue and green and red and...), we also take into consideration a subjective analysis. After all, you're not purchasing a monitor to view test patterns for hours on end. To see how the PQ321 performs in the real world, we viewed a series of high definition movies and fired up a few games. Torturous, we know, but hey, you guys are worth every minute of our entertainment.
    Subjective Tests
    HD Movie Playback and Gaming

    Elysium @ 4K

    You can find a bunch of 4K content on YouTube, including movie trailers, so that's what we did. It's impossible to capture the detail in a photo that's going to be viewed on a lower resolution monitor, leaving it up to us to offer up a subjective analysis. So, what's it like watching 4K content?

    At present, it's not terribly different than watching a Blu-ray. We can hear the movie buffs groaning, but in reality, the difference isn't as pronounced as it is when viewing 4K photos, though the subject matter plays a roll, too. As it pertains to movies, a 4K resolution allows you to sit closer to the screen before you start to notice abnormalities. On the flip side, 4K will lead to larger size screens, which is pretty exciting when there are already semi-affordable 70-inch LCD TVs on the market.

    Metro 2033 @ 4K

    If you're gaming on a Full HD 1080p monitor, stepping up to a 4K monitor like the PQ321 is a tremendous upgrade. There's more content and greater detail to enhance the gaming experience, provided your graphics card(s) can keep up. However, if you own a 30-inch class panel with 2560x1600 resolution (or thereabouts), the upgrade experience isn't quite as sublime, however it's still satisfying. That's not to say the PQ321 doesn't look fantastic when gaming -- it does -- we're just saying to temper your expectations if you're already accustomed to gaming on a high-resolution panel.

    We showed you earlier how to enable 60Hz on the PQ321, and if you plan to game, you'll definitely want to go that route. That means you'll need an NVIDIA GeForce 600 Series, 700 Series, or Titan graphics card, or an AMD Radeon HD 6000 or 7000 Series graphic card. You could also run the integrated graphics on Intel's Haswell chip, but good luck trying to drive a 4K resolution for gaming. The other option is to game at a lower resolution, and while the PQ321 handles them with aplomb, the process is clunky. Depending on the resolution you're after, you'll need to switch back to SST, let the monitor reboot, play with settings, etc. if you don't, you'll see a split screen when lowering the resolution in-game.

    To give you an idea what 4K gaming is like on the performance side, we ran some benchmarks with an XFX Radeon HD 7970 Black Edition card.
    Gaming & Web Browsing at 4K
    What is it like to game and browse the web on a 4K monitor? We're glad you asked. To find out, we ran some tests using a testbed consisting of an Intel Core i7 930 processor, ASUS P6X58D Premium motherboard, 4GB Corsair DDR3-1333 RAM, 240GB OCZ Vertex 3 solid state drive, XFX Radeon HD 7970 Black Edition graphics card, and Windows 8.1 Preview Edition. For the video card, we installed Catalyst 13.6 Beta.

    Metro 2033
    DX11 Gaming Performance

    Metro 2033 is your basic post-apocalyptic first person shooter game with a few rather unconventional twists. Unlike most FPS titles, there is no health meter to measure your level of ailment, but rather you’re left to deal with life, or lack there-of more akin to the real world with blood spatter on your visor and your heart rate and respiration level as indicators. The game is loosely based on a novel by Russian Author Dmitry Glukhovsky. Metro 2003 boasts some of the best 3D visuals on the PC platform currently including a DX11 rendering mode that makes use of advanced depth of field effects and character model tessellation for increased realism.

    There are a couple of things we can extrapolate from this test. First, gaming is possible on the PQ321's native resolution with a single graphics card, though there isn't much breathing room, even when running a high-end graphics card like the Radeon HD 7970. We saw over 38 frames per second in Metro 2033 at the Low setting with 4xAA and 16xAF. Turning those down bumps the framerates even higher and put us the neighborhood of 50fps. Not bad for 4K. Your mileage will vary depending on the game.

    The second thing take away from this is that you need some serious horsepower to drive a 4K display. Even though we managed playable framerates, higher settings take their toll, and that effect will only be enhanced on newer, more demanding games.

    Aliens vs Predator
    DX11 Gaming Performance

    Aliens vs Predator taps into your DirectX 11 hardware and takes advantage of geometry tessellation, advanced shadows, and other graphical goodies. The game itself is a science fiction first person shooter based on the Alien and Predator movie franchises and features a combination of characters and creatures from each one.

    Aliens vs Predator proved a lighter workout, allowing our testbed to pull over 50fps at the PQ321's native 4K resolution. Once again, as we crank up the settings, framerates fall off a cliff. Nevertheless, this reiterates that you can game on a 4K panel with the right GPU.

    Web Browsing

    Left to right: 100%, 125% and 150% font size

    At 4K, text starts to become hard to read. Most people will find text too densely packed, and depending on the font a particular website uses, you may need to increase the font size to 125 percent or even 150 percent (shown above from left to right is 100 percent, 125 percent, and 150 percent, though the effect won't be the same when viewed on a non-4K monitor. You can, however, get a sense of scale).

    Once you find a font size you're comfortable with, the PQ321 will start to shine, especially as you take advantage of all that real-estate with multiple windows. Simply put, there's a ton of space to work with. Note that you may also need to adjust the size of icons in Windows if you find yourself squinting.
    Performance Summary & Conclusion
    Performance Summary: Our first foray into both 4K and IGZO territory (on an official basis) left us impressed. The ASUS PQ321 represented the technologies well with superb color uniformity, a bright and densely detailed picture, and surprisingly good gaming performance devoid of nasty anomalies that can disrupt the experience. We did see a bit of overshoot -- not unusual for a high-end panel -- but it only manifested in DisplayMate's tests, not in real-world use. The PQ321 especially shows off its capabilities when viewing high-resolution photos with an incredible amount of detail.


    ASUS is first out of the gate with a consumer 4K Ultra HD monitor, and in essence the company has, by default, set the bar for others to follow. As such, it's impossible for us to know how it will stack up against the competition, though on its own merit, the PQ321 is a promising first effort, albeit a slightly unfinished one.

    The PQ321 is a little ahead of its time, not just in being a 4K monitor, but by wielding a 4K panel capable of 60Hz rather than 30Hz. To run at 60Hz off a single cable, you need to enable the multi-streaming transport (MST) capability in the PQ321's DisplayPort. After that, you have to mess around with updated drivers and GPU software settings, which is easy enough, but also a little annoying. Fortunately, ASUS is hard at work on updated firmware that will enable the monitor to automate the process; drivers will recognize when a 4K display has MST enabled and the panel will auto-configure itself. It's coming soon, and in fact we're holding onto the monitor for awhile in hopes of adding an updated impression.

    Until then, we can talk about the PQ321's other traits. We're impressed with how slim the monitor is, especially compared to the current crop of 30-inch LCD displays, and the overall design of the stand. Our only gripe is that the base of PQ321 doesn't offer rotation, though it does support height, tilt, and swivel adjustments. To put the panel in portrait orientation, you have to disassemble the base from the panel. Regardless, this is likely not much an issue, for most users considering a 32-inch panel like the PQ321.

    If you've never experienced a high-quality monitor before, firing up the PQ321 will change your outlook on things. Simply put, it's hard to go from a 4K resolution back down to 1080p, though it's a little easier to 'settle' for a 2560x1600 resolution, as is typical of 30-inch monitors. In fact, if you already own a 30-inch panel, we wouldn't suggest dropping $3,500 on a 4K upgrade, not unless you're a graphics professional who can truly take advantage of the added detail and real-estate. If that's the case, then by all means, treat yourself.  It really is an impressive, gorgeous display.

    The price tag is the real rub here, and not the lack of 4K content. That's always the case early in the game, as it is for the emerging 4K standard, but assuming you have the requisite disposable income and have no qualms spending it, the PQ321 will reward your investment with a brilliant display and a future-proof design, provided ASUS can deliver the promised firmware update. The PQ321 is a premium display, to be sure, and contrary to popular belief, you don't necessarily need dual-graphics cards to game on the panel's native resolution, though the extra horsepower of a second GPU certainly wouldn't hurt. We pulled upwards of 50fps running 4K on a Radeon HD 7970 GPU.

    While ASUS left some room for improvement, they ended up putting together a 4K monitor that represents this new class of ultra-high definition panels very well.



    • It's a 4K panel!
    • Excellent color uniformity
    • Can deliver 60Hz on a single cable
    • Gaming friendly
    • Did we mention it's a 4K panel?
    • Expensive
    • Rotating panel into portrait mode requires re-configuring the base.

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