Variable-refresh displays are one of the most exciting developments in PC gaming lately. For the first time, we’re not forced to choose between the lesser of two evils: ugly screen tearing or sluggish vsync. We get to enjoy a smooth, responsive experience with unmarred visual fidelity, often at frame rates that would make a console gamer blush.
Nvidia teamed up with display makers to bring us the first variable-refresh monitors last year, under the G-Sync umbrella. Since then, the open Adaptive-Sync standard has been added to the DisplayPort spec, and AMD has introduce its FreeSync initiative, which promises to endow Adaptive-Sync monitors with an extra layer of certification. AMD’s and Nvidia’s efforts bode very well for the adoption and democratization of variable-refresh monitors this year and beyond.
Of course, right now, Nvidia’s G-Sync is the only game in town. It’s the only port of entry into the wonderful world of variable-refresh goodness. And that means we’re still very interested to see what G-Sync displays are out there.
Today, we’re turning our attention to BenQ’s XL2420G, a 24″ offering that’s currently selling for about $580 at Newegg. This display is a little smaller and more affordable than some of the other G-Sync monitors we’ve looked at, but it’s not lacking in functionality or connectivity. Quite the opposite.
|Panel type||TN (8-bit)|
|Max. refresh rate||144Hz|
|Response time||1 ms (gray to gray)|
|Color gamut||72% NTSC|
|Viewing angles||170° horizontal
1x DisplayPort 1.2
1x USB (Type B)
|Outputs||2x USB 2.0
|Stand adjustments||Height, pivot, swivel, tilt|
BenQ outfits the XL2420G with a 1080p TN panel capable of refresh rates up to 144Hz and gray-to-gray response times as low as 1 ms. That high refresh rate makes the XL2420G perfect for G-Sync, and it also enables support for Nvidia’s 3D Vision stereoscopic technology, provided that you bring your own 3D Vision active-shutter glasses (another $150 at Newegg).
According to BenQ, the XL2420G can display eight bits per color channel and a 16.7-million color palette. The luminance and contrast ratings are more than respectable, as well, and the input selection is generous: dual-link DVI, DisplayPort 1.2, and dual HDMI. The monitor even doubles as a two-port USB 2.0 hub, and it can pipe HDMI audio through a 3.5-mm headphone jack. Then there’s the stand, which supports a full range of adjustments—assuming you don’t forgo it for a VESA mount, which the XL2420G also supports.
Going by the specs, the only sore spot seems to be the viewing angles. 170°/160° seems a little narrow in an age when IPS monitors are so ubiquitous. However, those angles are par for the course among TN panels, and you’ll be hard-pressed to find non-TN monitors that support refresh rates and response times as rapid as the XL2420G’s. More to the point, I’m only aware of one IPS display that supports G-Sync, and it’s not even out yet.
The BenQ XL2420G has one other notable trick up its sleeve. It’s equipped with two scalers: an Nvidia one for G-Sync and an additional scaler that drives what BenQ calls “Classic Mode.” The G-Sync scaler enables variable-refresh capabilities, while the Classic one offers more elaborate adjustment options and profiling capabilities. Switching between these scalers is done via the on-screen menu, and the inputs are partitioned between them. The DisplayPort input only works in G-Sync mode, while the DVI and HDMI ports are Classic Mode exclusives.
Despite the intriguing dual-scaler mojo, BenQ hasn’t forgotten about little ergonomic touches. The XL2420G’s stand has a carrying handle and a headphone hook, so you can hang your gaming cans without taking up unnecessary space. Below the hook is a cable-management hole with the same glossy red finish.
The monitor also ships with the S Switch, a rodent-like contraption that plugs into the monitor via Mini-USB and allows the user to control the on-screen display (OSD) menu and choose between profiles without holding their arm up at a 90-degree angle. Sadly, the S Switch is only usable in Classic Mode, so G-Sync users will have to leave it in the box.
Adjustments and ports
Before we test image quality and G-Sync gaming, let’s take a closer look at the BenQ XL2420G.
The stand allows the display to tilt forward 5° or back 20°, and it offers roughly 5.1″ of vertical adjustment wiggle room. The shots above show the monitor in its lowest position tilted as far as it can go, first forward and then back.
If you’re all about verticality, the XL2420G can also be used in portrait mode. Just remember to adjust the display to its maximum height before rotating it. I made the mistake of skipping that first step, and I wound up leaving a nice gash in the monitor’s base. Oops.
Not pictured: the stand’s ability to swivel 35° left or right, for a total range of movement of 70°. Swiveling can be helpful, but it’s not crucial, since grabbing hold of the base and turning the whole thing works well enough in a pinch. That fact holds especially true for the XL2420G, which is a relative featherweight at only 13 lbs.
Here are the inputs. That big, squarish one on the right is the USB Type-B port that powers the monitor’s built-in hub. On the very left, next to the DVI connector, is a Mini-USB port for the S Switch contraption. All of these ports are labeled on the monitor’s back surface, so you don’t (necessarily) need to poke your head under the thing to see what you’re doing.
Rounding out the XL2420G’s connectivity are the USB 2.0 hub and headphone jack, which sit on the left side of the display, about 3.5″ from the bottom edge. I rarely run out of front-panel USB ports on my PC, but it’s nice to have options. Interference-prone wireless dongles might work better in this spot than under a desk, too.
The OSD controls
BenQ has given the XL2420G some unusual controls for its on-screen display.
Instead of buttons, this monitor has six touch-sensitive contacts, all recessed slightly. Five of the contacts control the OSD functions, while the sixth is a sleep/wake toggle. Below that toggle is an infrared transmitter for synchronizing with Nvidia’s active-shutter 3D Vision glasses.
You’d expect these controls to be hard to see and operate in the dark, but they’re not. That’s because the buttons automatically light up when your finger gets within about a quarter inch of them, or as soon as you touch the lower quarter of the screen’s right edge. Move your hand away, and they go dark again. The contacts also beep when touched, which makes up for the lack of tactile feedback to some degree. In practice, this system feels seamless and works very reliably. Nice job, BenQ.
Then there’s the S Switch. It’s too bad this device doesn’t work in the G-Sync mode, because it really is an interesting and unique alternative to the default OSD controls. It latches on magnetically to either side of the display’s base, and it lets you scroll through the OSD with the red wheel. A wheel click activates a selected option, while the back button takes you up a step in the menu tree. The 1, 2, and 3 buttons call up the custom profile slots.
The S Switch works rather well, although I should note that it doesn’t have an optical sensor underneath, despite what its mouse-like shape might suggest. The wheel and buttons are all she wrote.
The OSD interface
The XL2420G actually has two OSD interfaces: one for the G-Sync scaler and another for Classic Mode. The screenshot below shows the G-Sync OSD, but you can use the buttons underneath to see the Classic Mode OSD.
The two interfaces look and behave a little differently, and they each expose a different set of features. This chart from BenQ’s website breaks down some of the differences:
Notably missing from the G-Sync OSD are Display Mode, which lets the XL2420G simulate smaller display sizes through a clever application of black borders, and Smart Scaling, which gives the user control over how big simulated display sizes appear on the screen.
BenQ’s Windows software is also out of bounds to the G-Sync mode. That software comprises Display Pilot and the Game Mode Loader.
Display Pilot is a substitute for the OSD with a number of extra features, such as desktop partitioning. The Game Mode Loader, meanwhile, allows third-party profiles to be downloaded and saved into the display’s memory. The XL2420G has three custom profile slots, which can also be filled with custom settings defined through the OSD, the old fashioned-way.
Other Classic Mode exclusives include Instant Mode, which is supposed to cut input lag, and Smart Focus, which lets you zoom in on a portion of the screen, like a YouTube video. We didn’t dwell on either those features—or the Windows software—since we were more interested in the G-Sync side of the XL2420G.
One OSD setting that’s present in both G-Sync and Classic modes is AMA, or Advanced Motion Accelerator. BenQ says this feature raises the voltage applied to the panel’s liquid crystals in order to improve gray-to-gray response times. The OSD presents three AMA settings: Off, High, and Premium. Here they are in action in Blur Busters’ UFO Test:
Leaving AMA off clearly increases visible ghosting, so objects moving across the screen appear sort of smeared. The effect is somewhat subtle, though, and I honestly can’t see much of a difference between the High and Premium settings. I wound up leaving the display on the High setting, the default, throughout testing.
Our testing methods
We’ve changed our testing methods up a bit since our last monitor review. Or, rather, I took some creative license to get around a small logistical problem.
The colorimeter on hand at TR’s northern outpost is EyeOne’s Display 2, whose bundled calibration software is close to a decade old and no longer supported. Rather than use deprecated software, I installed dispcalGUI, a calibration and characterization utility powered by the open-source Argyll Color Management System. dispcalGUI is a little more daunting and less user-friendly than consumer calibration software, but it’s very powerful and quite a bit more feature-packed. Not only that, but it features more complete characterization functionality than HCFR, the tool we’ve used to test displays in the past.
So, I’d call this change a win-win.
Using dispcalGUI and our trusty colorimeter, I’ll be comparing the XL2420G to my daily driver, the 24″ HP ZR24W. The ZR24W retailed for around $400 when it came out roughly five years ago. Because it has an IPS panel and a 60Hz non-variable refresh rate, it’s obviously in a very different league than the BenQ XL2420G. However, it should provide a helpful frame of reference on the image quality front. If the XL2420G can come close to the same level of color accuracy as an IPS monitor, then we’ll know BenQ has a winner on its hands.
Luminance and contrast
We’ll start by measuring black and white luminance at each display’s minimum and maximum brightness settings. We can then compute contrast from those numbers. Note that we’re testing the XL2420G in both G-Sync and Classic modes, and we’re taking an additional set of readings at a normalized luminance setting of 120cd/m².
Thanks to its powerful LED backlight, the BenQ XL2420G runs circles around the CCFL-backlit HP monitor, be it in terms of peak brightness, contrast, or even black level.
Curiously, though, the BenQ monitor is measurably brighter—and has a measurably higher contrast ratio—in Classic Mode than it is with the G-Sync scaler enabled. The G-Sync mode isn’t murky by any means, however, and 442 cd/m² seems almost blindingly bright to me in an indoor setting.
Color gamut, temperature, and gamma
For this section, we’ll run both the BenQ and HP monitors through a gauntlet of tests first in their default, uncalibrated state, and then after calibrating them with dispcalGUI. Luminance will be normalized at 120 cd/m² throughout.
Both displays stick pretty closely to the sRGB color gamut, which is represented by the dotted triangle in the middle of the image. However, the HP ZR24W’s gamut coverage is narrower, and its color temperature is way off in its uncalibrated state. (The color temperature is indicated by the white cross. Ideally, the white cross should overlap with the gray X, which stands for a 6500K color temperature—roughly equivalent in practice to the sRGB standard’s D65 illuminant.)
Even uncalibrated, the BenQ panel does a fair job of sticking to the 6500K sweet spot. For the most part, anyway. My old ZR24W is another story: uncalibrated, with OSD set to the 6500K default, its color temperature is closer to 5500K.
Early reviews of the HP ZR24W, like this one by TFT Central, show a default color temperature above 6500K at the same setting, so I can only conclude that my unit is a victim of old age. According to this NEC whitepaper, as CCFL-backlit monitors age, their white point shifts “toward a yellow hue.” I guess it’s time to retire the old workhorse . . . but not before we run more tests.
Gamma readings are all pretty close to the 2.2 sweet spot, both before and after calibration.
That said, the BenQ XL2420G needs a fair amount of warming up to get to that point. Here are gamma readings taken just 30 minutes after the two displays were powered on:
The ZR24W is already at 2.2 after half an hour, but the XL2420G is around the 1.9 mark, which translates into a paler, more washed-out image. The BenQ monitor’s gamma inches slowly toward 2.2 as the panel continues to warm up, but it’s a little jarring during the first 45 minutes of use.
I’m not going to get into the weeds of explaining the delta-E metric, since there’s some serious math involved. All you need to know is that delta-E figures help us quantify the difference between the colors our displays produce and the colors they ought to produce, according to the sRGB standard.
dispcalGUI defines “nominal” delta-E 2000 values as no more than 1.5 on average, with an absolute maximum of 4.0. “Recommended” values are no more than 1.0 on average and 3.0 at most.
I’m not sure why the blue readings are so high across these two displays. Perhaps we need to pony up for a better calibrator here at TR North. In any case, these numbers show the XL2420G compares very well to the aging, IPS-based ZR24W. The XL2420G achieves lower average and maximum delta-E values both calibrated and uncalibrated in G-Sync mode. The uncalibrated readings in Classic Mode are a fair bit higher, though.
To see how uniform the BenQ XL2420G’s backlight is, we’re going to use dispcalGUI to grab luminance readings at 15 spots across the panel, with the center normalized to 120 cd/m².
As always, note that these are luminance numbers measured with a colorimeter. The subjective impression of brightness one gets from looking at the screen is a little different. With the naked eye, the XL2420G seems pretty darned uniform when displaying a solid white image—though there is a very slight shadow in the upper-left corner. That’s not going to bother you when you’re immersed in a gaming session, though.
This overexposed photo shows the XL2420G rendering a black screen. The idea here is to get a sense of backlight bleeding:
There’s a teeny bit of unevenness along the left side, plus some slightly lighter spots at the top and bottom edges. But man, this is nothing compared to some of the backlight bleeding we’ve on some other displays. I’d say BenQ did a pretty stellar job here.
Our viewing angle test involves snapping pictures with the display facing the camera, then leaning forward 10°, leaning back 10°, and turned 20° toward the side. Our test image is a scene from new zombie parkour extravaganza Dying Light.
Those viewing angles aren’t great, but this what we’ve come to expect from TN panels. Besides, narrow viewing angles aren’t much of an annoyance on desktop monitors. On a notebook, the user’s position relative to the screen is liable to change frequently. But on a desktop, the user is likely to sit in the same spot at all times, unless he’s, like, really terrible about slouching.
I unfortunately don’t have a CRT monitor on hand to act as a baseline for input lag measurements. However, I can compare the XL2420G to the ZR24W using our high-speed camera and the Lagom response time test.
Left: HP’s ZR24W. Right: BenQ’s XL2420G in G-Sync mode.
The XL2420G is noticeably more responsive than my old IPS monitor. I measured the delta between the two panels at 13-15 ms. Using XL2420G for the first time was kind of a throwback to the olden days, when I upgraded from a 1GHz Athlon to an Athlon XP 2500+. Objects on the screen responded to input so much more quickly that they almost seemed to do so before being clicked. I guess one should expect no less from an ultra-fast gaming monitor, but it’s nice to know the XL2420G delivers.
As always, we’re taking power consumption readings at the wall outlet using a P3 Kill A Watt power meter.
We saw earlier that the XL2420G’s Classic Mode is brighter than the G-Sync mode. It’s therefore a little surprising to see that the Classic Mode also has lower power draw. If I were a betting man, I’d put my money on Nvidia’s G-Sync FPGA chip being more power-hungry than the Classic Mode scaler, which is likely a smaller ASIC.
Aside from brief glimpses, I’d never taken a really good look at a G-Sync monitor before the BenQ XL2420G hit my lab. I’d heard all the hype and read Scott’s primer on the subject, and I was reasonably sure the excitement was justified. However, I’d had plenty of fun playing games on 60Hz monitors. I was therefore curious to see whether G-Sync could improve my gaming experience enough to make it seem indispensable.
The answer is a pretty unequivocal yes. But the reasons are a little hard to explain, unless you’ve physically used a G-Sync monitor yourself.
Videos like the one above show how G-Sync eliminates screen tearing, but they don’t convey a sense of what G-Sync feels like when you’re playing a game. The best analogy I can come up with is this one: it’s like watching The Hobbit at 48 FPS. You get a very clear sense of extra fluidity from the 144Hz peak refresh rate, and the lack of either screen tearing or vsync-induced slowdowns means the animation is always perfect—or as perfect as the GPU can make it.
The result is something much less abstract than usual. There are fewer kinks, in other words, to make you go, “Oh, this is a video game running on a computer.” Depending on how good the graphics are in whatever game you’re playing, the effect can be a little jarring at first. You’re less liable to overlook artistic flaws, just as people watching The Hobbit had trouble overlooking obvious makeup prosthetics.
You get used to it, though. After a while, the immediacy of the input response and the flawlessness of the animation make G-Sync kind of intoxicating. Going back to a 60Hz monitor feels a bit like digging up a 15″ CRT from 1995. The sense that you’re missing out is obvious and kind of heart-wrenching.
So, yeah. Totally worth it.
Before I render my final verdict, a few words about the panel’s overall image quality. As many of you know, using a TN panel often feels like something of a downgrade if you’re used to IPS panels. The XL2420G largely mitigates that with great color reproduction, high contrast, and good panel uniformity. The issue of the narrower viewing angles does rear its head more often than with an IPS panel, and that can be mildly frustrating. The fact that the XL2420G takes a long time to warm up and pull the gamma out of bizarro world adds to that frustration. But after you’ve been gaming for a couple of hours, my impression is that the downsides are easily forgotten.
There you have it, then. The BenQ XL2420G is an excellent little monitor, and I definitely enjoyed my time with it.
Sure, the thing isn’t absolutely perfect. I’d have preferred if BenQ lopped off the Classic Mode and cut the price by a few bucks, for starters. (I doubt the target audience for this display cares about features that are off-limits in G-Sync mode.) The narrow viewing angles and long warmup time can be annoying, and it’d be nice if the built-in USB hub was of the SuperSpeed variety.
At $580.99 shipped, however, the XL2420G is a nice entry point into the world of variable-refresh monitors. Its only competition in that price range seems to be Acer’s XB270H Abprz, which spreads the same 1920×1080 resolution across a larger 27″ panel. I don’t know about you, but I’m not thrilled about the relatively low pixel density that arrangement entails.